Quiz Electronics Engineering 24 Sep 2020

Quiz Electronics Engineering
Exam: NIC
Topic: Miscellaneous
Date: 24/09/2020

Each Question carries 1 Mark
Negative Marking: 1/4
Time: 10 Minutes

Q1. The modulation index of a narrowband FM signal is
(a) nearly equal to 1
(b) equal to 1
(c) much greater than 1
(d) 40 percent

Q2. In a microprocessor –
(a) one machine cycle is equal to one clock cycle
(b) one clock cycle consists of several machine cycle
(c) one machine cycle is always less than one clock cycle
(d) one machine cycle consists of several clock cycles

Q3. For a series as well as parallel circuit
(a) Resistance are additive
(b) Powers are additive
(c) Currents are additive
(d) Voltage drops are additive

Q4. Which of the following is the multiple access protocol for channel access control?
(a) CSMA/CD
(b) CSMA/CA
(c) HDLC
(d) Both CSMA/CD & CSMA/CA

Q5. An LTI system is causal if and only if
(a) h(t) is finite for t < 0.
(b) h(t) is finite for 0 < t < ∞.
(c) h(t) = 0 for t < 0
(d) h(t) is non-zero for all t.

Q6. The figure given below represents …….. operation.

(a) NAND
(b) OR
(c) EX-OR
(d) AND

Q7. The dimension of flux density is
(a) MT^(-2) Q^(-2)
(b) MT^(-1) Q^(-1)
(c) MT^1 Q^1
(d) MT^(-1) Q^(-2)

Q8. The transfer function of any stable system which has no zeros or poles in the right half of the s-plane is said to be
(a) Minimum gain transfer function
(b) non-minimum phase transfer function
(c) Minimum frequency response function
(d) minimum phase transfer function

Q9. Thermocouple is based on
(a) Seebeck’s effect
(b) Thomson
(c) Joule’s law
(d) None of these

Q10. Assertion(A): Zero input response is the natural response with zero initial conditions.
Reason(R): Zero state response is the response with given input with zero initial condition.
(a) Both A and R are True and R is the correct explanation of A.
(b) Both A and R are True but R is not the correct explanation of A.
(c) A is True but R is False.
(d) A is False but R is True.

SOLUTIONS

S1. Ans.(a)
Sol. Narrow Band Frequency modulation(NBFM) has a smaller bandwidth when compared to Wide Band Frequency modulation (WBFM). The modulation index nearly equal to 1.

S2. Ans.(d)

S3. Ans.(b)
Sol. Powers are additive in both series as well as parallel circuit.

S4. Ans.(d)
Sol. CSMA/CD stands for Carrier Sense Multiple Access / Collision Detection and CSMA/CA stands for Carrier Sense Multiple Access / Collision Avoidance. CSMA/CD protocol is effective after a collision i.e. detects a collision, whereas CSMA/CA protocol is effective before a collision i.e. prevents collision. These protocols are used for efficient carrier transmission through multiple channel access.

S5. Ans.(c)

S6. Ans (a)
Sol. We can check by finding the Truth Table of the above given figure.
Truth Table:
A B Y
0 0 1
0 1 1
1 0 1
1 1 0
The Truth Table is similar to that of NAND gate.

S7. Ans.(b)

S8. Ans.(d)

S9. Ans.(a)
Sol. Thermocouple is based on Seebeck’s effect.

S10. Ans.(d)
Sol. In case of Zero input response, initial condition must not be zero.

Quiz Electronics Engineering 22 Sep 2020

Quiz Electronics Engineering
Exam: NIC
Topic: Miscellaneous
Date: 22/09/2020

Each Question carries 1 Mark
Negative Marking: 1/4
Time: 10 Minutes

Q1. Communication channel is shared by all the devices on the network in
(a) unicast network
(b) broadcast network
(c) multicast network
(d) anycast network

Q2. If a continuous time signal x(t) can take on any value in the continuous interval(-∞, ∞), it is called
(a) Deterministic signal
(b) random signal
(c) analog signal
(d) digital signal

Q3. Power factor of the system is kept high
(a) to reduce line losses
(b) to maximize the utilization of the capacities of generators, lines and transformers
(c) to reduce voltage regulation of the line
(d) due to all above reasons

Q4. The binary addition of 1111 and 1011 is
(a) 1010
(b) 11010
(c) 110010
(d) 11100

Q5. Consider the following statements regarding an electrostatic field:
1. It is irrotational.
2. It is solenoidal.
3. It is static only from a macroscopic view point.
4. Work done in moving a charge in the field from one point to another is independent of the path of movement.
Which of these statements are correct?
(a) 1, 2 and 3
(b) 1, 2 and 4
(c) 1, 3 and 4
(d) Only 2 and 4

Q6. The types of carriers in a semiconductor are
(a) 1
(b) 2
(c) 3
(d) may be 1 or 2 depending on material

Q7. The software used to drive microprocessor based system is called
(a) assembly language
(b) firmware
(c) High Level Language
(d) Basic Interpreter Instruction

Q8. The ramp function can be obtained from the unit impulse at t = 0 by
(a) differentiating unit impulse function once
(b) differentiating unit impulse function twice
(c) integrating unit impulse function once
(d) integrating unit impulse function twice

Q9. The spectral density of white noise is
(a) independent of frequency
(b) independent of noise power
(c) dependent on frequency
(d) none of the above

Q10. Network congestion occurs _________
(a) in case of transfer failure
(b) when a system terminates
(c) in case of traffic overloading
(d) when connection between two nodes terminates

SOLUTIONS

S1. Ans.(b)
Sol. In broadcast network same information is transmitted to a large number of devices. For transmission same channel is used.

S2. Ans.(c)

S3. Ans (d)
Sol. Due to High Power Factor: –
the load draws less current than in case of low power factor. In case of low power factor, the line losses will increase and to bear that current more amount of Aluminium and Copper is required.
there is small voltage drop so better Voltage Regulation obtained.
there is possibility of removal of flow of reactive power.

S4. Ans.(a)
Sol.

S5. Ans.(c)
Sol. Electric Field has
∇ × E ⃗ = 0; so irrotational
∇.E ⃗ ≠ 0; so not solenoidal

S6. Ans. (b)
Sol. The types of carriers in a semiconductor are 2 i.e. electrons and holes.

S7. Ans.(a)

S8. Ans.(d)
Sol. Ramp function is integration of unit step function and unit step function is integration of unit impulse function.
So, The ramp function can be obtained from the unit impulse at t = 0 by double integration of unit impulse function.

S9. Ans.(a)
Sol. Sx(f) = No/2, for all f. The spectral density of white noise is independent of frequency.

S10. Ans.(c)
Sol. If network or any link is carrying data more than the limit it can handle, then network congestion occurs.

Quiz Electronics Engineering 21 Sep 2020

Quiz Electronics Engineering
Exam: NIC
Topic: Miscellaneous
Date: 21/09/2020

Each Question carries 1 Mark
Negative Marking: 1/4
Time: 10 Minutes

Q1. If X(ω) = 𝛿(ω – ω_o), then x(t) is
(a) e^(-jω_o t)
(b) 𝛿(t)
(c) 1/2π e^(jω_o t)
(d) 1

Q2. The waveguide modes are usually excited from a signal source through
(a) a coaxial cable
(b) an aperture
(c) an antenna
(d) free-space coupling

Q3. Which of the following is used for serial access storage –
(a) RAM
(b) Magnetic Tape
(c) Magnetic Disk
(d) Core Memory

Q4. The hexadecimal equivalent of 1110011011110101 is
(a) E67F
(b) E76F
(c) E7F5
(d) E6F5

Q5. What is SIM in microprocessor?
(a) Signal Interrupt Mask
(b) Set Interrupt Mask
(c) Select Interrupt Mask
(d) Sorting Interrupt Mask

Q6. A sinusoidal signal of amplitude A is quantized by a uniform quantizer. Assume that the signal utilities all the representation levels of the quantizer. If the Signal to Quantization ratio is 31.8 dB, the number of levels in the quantizer will be
(a) 32
(b) 16
(c) 64
(d) 8

Q7. The voltage in a circuit follows the law V = 100 sin⁡ωt. If the frequency is 25 Hz, how long will it take for the voltage to rise to 50 volts?
(a) 1/50s
(b) 1/100s
(c) 1/300s
(d) 1/600s

Q8. The fourier transform of a function is equal to its two-sided Laplace transform evaluated
(a) on the real axis of the s-plane
(b) on the imaginary axis of the s-plane
(c) on a line parallel to the real axis of the s-plane
(d) on a line parallel to the imaginary axis of the s-plane

Q9. The Address Resolution Protocol (ARP) is used for
(a) Finding the IP address from the DNS
(b) Finding the IP address of the default gateway
(c) Finding the IP address corresponds to a MAC address
(d) Finding the MAC address that corresponds to an IP address

Q10. The transconductance is measured in
(a) mhos
(b) amperes
(c) ohms
(d) volts

SOLUTIONS

S1. Ans.(c)
Sol. In Fourier Transform –
e^(+jω_o t).x(t) ↔┴( F.T ) X(ω – ω_o)
1 ↔┴( F.T ) 2π𝛿(ω)
Now,
e^(+jω_o t).1 ↔┴( F.T ) 2π𝛿(ω – ω_o)
⇒ 1/2π e^(+jω_o t) ↔┴( F.T ) 𝛿(ω – ω_o)

S2. Ans.(a)

S3. Ans.(b)

S4. Ans.(d)
Sol. We know that one digit in Hexadecimal is equivalent to 4 binary digits.
Here, Grouping binary numbers in a group of 4 we get,
⏟1110┬(↓┬E ) ⏟0110┬(↓┬6 ) ⏟1111┬(↓┬F ) ⏟0101┬(↓┬5 )
Therefore, The hexadecimal equivalent of 1110011011110101 is E6F5.

S5. Ans.(b)
Sol. SIM stands for Set Interrupt Mask which is handling the interrupts in 8085 microprocessors.

S6. Ans.(a)
Sol. Given:
SQNR = 31.8 dB
SQNR of a uniform quantized sinusoidal signal is given by
SQNR in dB = 1.8 + 6n where, n is number of bits
Now,
31.8 = 1.8 + 6n
⇒ 6n = 31.8 – 1.8 = 30
∴ n = 5
Therefore, Number of quantized level = 2n = 25 = 32

S7. Ans.(c)
Sol. Given:
V = 50 Volt
f = 25 Hz
Here,
⇒ ω = 2πf = 2π × 25
∴ ω = 50π
Now,
⇒ 50 = 100sinωt
⇒ sinωt = 50/100 = 1/2
⇒ ωt = π/6
⇒ 50πt = π/6
⇒ t = π/(50π × 6)
So, t = 1/300 sec

S8. Ans.(b)
Sol. Relation between Fourier Transform and Laplace Transform: –
As s = σ + jω
F(σ + jω) = ∫_(-∞)^∞▒〖f(t)〗 e^(-σt) e^(-jωt)dt = e^(-σt)F(ω)
When σ = 0, then LT becomes FT.

S9. Ans.(d)
Sol. ARP discovers the hardware address, also called Media Access Control (MAC) address of a host from its known IP address.

S10. Ans.(a)
Sol. The unit of transconductance is similar to unit of conductance. It is measured in Siemens also represented as mho.

Quiz Electronics Engineering 19 Sep 2020

Quiz Electronics Engineering
Exam: NIC
Topic: Miscellaneous
Date: 19/09/2020

Each Question carries 1 Mark
Negative Marking: 1/4
Time: 10 Minutes

Q1. An Ethernet hub
(a) connects to a digital PBX
(b) Functions as a repeater
(c) connects to a token-ring network
(d) functions as a gateway

Q2. Norton’s Theorem is
(a) The same as Thevenin’s theorem
(b) Same as Newton’s theorem
(c) Converse of Thevenin’s theorem
(d) Cannot say

Q3. In an n-type semiconductor, as the donor concentration increases, the Fermi levelE_F:
(a) Moves towards the conduction band
(b) Remains unaltered
(c) Move towards the centre of forbidden energy gap
(d) May or may not move depending on temperature

Q4. In an unclocked R-S flip flop made of NOR gates, the forbidden input condition is:
(a) R = 0, S = 0
(b) R = 1, S = 0
(c) R = 0, S = 1
(d) R = 1, S =1

Q5. The each with a 1mm separation in air is
(a) 9 × 10^(-9) N
(b) 9 × 10^(-6) N
(c) 9 × 10^(-3) N
(d) 9 × 10^(-12) N

Q6. What is the purpose of the CRC in network communications?
(a) Request retransmission of lost packets
(b) Detect data errors
(c) Detect lost data packets
(d) Reassemble packets into their original order

Q7. Which of the following is not true about EPROM?
(a) Random Access Memory
(b) Erasable Programmable Read Only Memory
(c) Non-volatile Memory
(d) Sequential Access Memory

Q8. An upward counter can count in …. direction
(a) forward
(b) backward
(c) both (a) and (b)
(d) either (a) or (b)

Q9. If the radiated power of AM transmitter is 10 kW, the power in the carrier for modulation index of 0.6 is nearly:
(a) 8.24 KW
(b) 9.26 KW
(c) 9.6 KW
(d) 8.47 KW

Q10. Power factor of the magnetizing component of a transformer is
(a) Unity
(b) 1
(c) Zero
(d) Greater than 1

SOLUTIONS

S1. Ans.(b)
Sol. An Ethernet Hub functions as a repeater. In Telecommunication, a repeater is an electronic device which retransmits the received signal at a higher power. It is used for increasing signal strength.

S2. Ans.(c)
Sol. In Norton’s equivalent Circuit, Norton resistance is connected in parallel with the Norton Current source but in Thevenin’s equivalent circuit, Thevenin resistance is connected in series with the Thevenin Voltage source. Hence, Norton’s theorem is converse of Thevenin’s theorem.

S3. Ans.(a)

S4. Ans.(d)
Sol. The unclocked R-S flip flop made of NOR gates is equivalent to the RS latch circuit. So, The forbidden input condition in RS latch circuit is R = 1, S = 1.

S5. Ans.(c)
Sol. Given:
Q_1 = Q_2 = 1 nC = 10^(-9) C
r = 1mm = 10^(-3) m
We know that,
K = 9 × 10^9 Nm^2/C^2
According to Coulomb’s Law –
F = (KQ_1 Q_2)/r^2
Now,
F = (9 × 10^9 × 10^(-9) × 10^(-9) )/〖(10^(-3))〗^2
⇒ F = (9 × 10^(-9) )/10^(-6)
So, F = 9 × 10^(-3) N

S6. Ans.(b)
Sol. The Cyclic Redundancy Check (CRC) ) is an error-detecting code commonly used in digital networks and storage devices to detect corrupted data. The sending device calculates the CRC and adds it to the frame. The receiving device calculates the CRC when the frame is received. If the CRCs do not match, the frame has been corrupted or altered. Blocks of data entering these systems get a short check value attached, based on the remainder of a polynomial division of their contents. The most common method of correcting errors is to request retransmission of the original frame.

S7. Ans.(a)
Sol. EPROM is a Non-volatile Read Only Memory and not Random Access Memory.

S8. Ans. (c)
Sol. An upward counter can count both in forward and backward direction.

S9. Ans.(d)
Sol. Given:
Radiated power (Pt) = 10kW
Modulation index (µ) = 0.6
We know that,
Pt = Pc [1+ µ^2/2]
Now, 10 = Pc [1+ 〖0.6〗^2/2]
⇒ 10 = Pc [1+0.18]
So, Pc = 10/1.18 = 8.47 KW
Therefore, The power in the carrier for modulation index of 0.6 is nearly 8.47 KW.

S10. Ans.(a)

Quiz Electronics Engineering 18 Sep 2020

Quiz Electronics Engineering
Exam: NIC
Topic: Miscellaneous
Date: 18/09/2020

Each Question carries 1 Mark
Negative Marking: 1/4
Time: 10 Minutes

Q1. The number of layers in ISO OSI reference model is
(a) 5
(b) 6
(c) 7
(d) None of these

Q2. A capacitor opposes
(a) Change in voltage
(b) Change in current
(c) Both change in voltage and current
(d) None of these

Q3. In a discrete-time Low Pass Filter, the frequency response is
(a) a periodic
(b) a periodic with response restricted to (〖-ω〗_c to +ω_c)
(c) periodic with period 2π.
(d) Quasi periodic with response extending to infinity

Q4. 8085 Microprocessor does not have:
(a) Over Flag
(b) Parity Flag
(c) Zero Flag
(d) Auxiliary Carry Flag

Q5. TCP/IP model does not have ______ layer but OSI model have this layer.
(a) network layer
(b) transport layer
(c) application layer
(d) session layer

Q6. Which of the following device has characteristic close to that of an ideal voltage source?
(a) Crystal diode
(b) Vacuum diode
(c) Zener diode
(d) All of the above

Q7. A deterministic signal has power spectrum given in figure. The minimum sampling rate needed to completely represent signal is

(a) 1 kHz
(b) 4 kHz
(c) 3 kHz
(d) 4 Hz

Q8. Which statement is correct:
(a) HLDA signal generated by DMA controller
(b) HLDA signal generated by DMA controller for 8085
(c) HOLD signal is generated by 8085 for DMA controller
(d) HLDA signal is generated by 8085 for DMA controller

Q9. Assertion(A): A Look-Ahead Carry adder is a fast adder.
Reason(R): A Parallel Carry Adder generates sum digits from the input digits.
(a) Both A and R are True and R is the correct explanation of A.
(b) Both A and R are True but R is not the correct explanation of A.
(c) A is True but R is False.
(d)A is False but R is True.

Q10. The flux and potential functions due to a line charge and due to two concentric circular conductors are of the following form:
(a) Concentric circular equipotential lines and straight radial flux lines.
(b) Concentric circular flux lines and straight equipotential lines
(c) equipotential due to line charge are concentric cylinders and equipotential due to two conductors are straight lines.
(d) Equipotential due to line charge are straight flat surfaces and those due to two conductors are concentric cylinders.

SOLUTIONS

S1. Ans.(c)
Sol. There are 7 layers in the OSI(Open System Interconnection) model. Those are – Application Layer, Presentation Layer, Session Layer, Transport Layer, Network Layer, Data Link Layer and Physical Layer.

S2. Ans.(a)
Sol. If capacitors supports sudden change in voltage then it requires large amount of current which is tending to infinity to flow through low impedance capacitor. This infinity current is not possible. Hence, Capacitor opposes sudden change in voltage.

S3. Ans.(c)
Sol. Sampling in one domain leads to periodicity in other domain.

S4. Ans.(a)
Sol. There are 5 flags in the flag register of 8085 microprocessor. Each flag is a 1-bit flip-flop which holds the status of the accumulator after execution of any instruction.

S5. Ans.(d)
Sol. In OSI model, there are three layers which are not present in TCP/IP model. Those are Presentation and Session layer.
Application, Presentation and Session Layer are combined as Application Layer in TCP/IP.
Data Link Layer and Physical Layer is combined as Network Access Layer.

S6. Ans.(c)
Sol. Ideal voltage source has internal resistance zero so voltage remains constant w.r.t change in current. A Zener diode, when reversed biased acts as a constant voltage source. So, its characteristics matches to that of ideal voltage source.

S7. Ans.(b)
Sol. Given:
fmax = 2 kHz
We know that, minimum sampling rate is
(fs)min = 2 fmax = 2 x 2 kHz = 4kHz
Therefore, Minimum sampling rate is 4kHz.

S8. Ans.(d)
Sol. ‘HLDA’ is a Hold Acknowledgement signal generated by 8085 microprocessor for DMA controller. It gives signal to allow direct access of the memory.
HOLD signal is generated by DMA controller and when it is ‘HIGH’ then it instructs processor that another master is calling for this line.

S9. Ans.(a)

S10. Ans.(c)

Quiz Electronics Engineering 17 Sep 2020

Quiz Electronics Engineering
Exam: NIC
Topic: Miscellaneous
Date: 17/09/2020

Each Question carries 1 Mark
Negative Marking: 1/4
Time: 10 Minutes

Q1. What will be the equipotential surfaces for a pair of equal and opposite line charges?
(a) Non-concentric cylinders
(b) Concentric Cylinders
(c) Spheres
(d) None of the above

Q2. Regarding charging of a capacitor which statement is false?
(a) the amount of time necessary to discharge a capacitor depends on its size and its series resistor
(b) time constant of an R-C circuit is the time required to charge the capacitor to 70.7% of the applied voltage
(c) five time-constants are necessary to charge the capacitor to 99 per cent of the applied voltage (or full charge).
(d) the value of one time constant = CR

Q3. Consider sinusoidal modulation in AM system. Assuming no overmodulation, the modulation index(µ) when the maximum and the minimum value of the envelope, respectively, are 3 V and 1V, is
(a) 1/3
(b) 1/5
(c) 2
(d) 1/2

Q4. Which one of the following relations is not correct?
(a) f(t)𝛿(0) = f(0)𝛿(t)
(b) ∫_(-∞)^∞▒〖f(t)δ(τ)〗dt = 1
(c) ∫_(-∞)^∞▒δ(τ) dt = 1
(d) f(t)𝛿(t – τ) = f(τ)𝛿(t – τ)

Q5. The output of an AND gate with three inputs, A, B, and C, is HIGH when ________:
(a) A = 1, B = 1, C = 0
(b) A = 0, B = 0, C = 0
(c) A = 1, B = 1, C = 1
(d) A = 1, B = 0, C = 1

Q6. In sign magnitude numbers:
(a) maximum bit 0 stands for positive numbers
(b) maximum bit always 1
(c) maximum bit 0 stands for negative numbers
(d) maximum bit 1 stands for positive numbers

Q7. Local area networks can transmit
(a) Faster than telecommunications over public telephone lines.
(b) Using twisted-pair wiring or coaxial cables
(c) Slower than telecommunications over pubic telephone lines.
(d) Both (a) and (b)

Q8. The minimum voltage along a transmission line is 260 V, while the maximum is 390 V. The SWR is
(a) 0.5
(b) 1.1
(c) 1.25
(d) 1.5

Q9. Resistance of a conductor is proportional to its
(a) length
(b) width
(c) both (a) and (b)
(d) none of these

Q10. A capacitor with no initial charge at t=∞ acts as
(a) voltage source
(b) current source
(c) short-circuit
(d) open-circuit

SOLUTIONS

S1. Ans.(a)

S2. Ans.(b)

S3. Ans.(d)
Sol. Given:
The minimum value of the envelope(Amin) = 1 V
The maximum value of the envelope(Amax) = 3 V
We know that, the modulation index is
µ = (A_(max )- A_min)/(A_(max )+ A_min )
Now,
µ = (3 – 1)/(3 + 1) = 2/4
∴ µ = 1/2

S4. Ans.(b)
Sol. ∫_(-∞)^∞▒〖f(t)δ(τ)〗 = 1 is not a property of a delta function.
(i) Sampling Property
f(t).𝛿(t) = f(0)𝛿(t)
f(t).𝛿(t – a) = f(a).𝛿(t – a)
(ii) Shifting Property
∫_(-∞)^∞▒〖f(t).δ(t)〗dt = f(0)
∫_(-∞)^∞▒〖f(t).δ(t-a)〗dt = f(a)
(iii) Scaling Property
𝛿(at) = 1/|a| 𝛿(t)
𝛿(at ± b) = 1/|a| 𝛿(t ± b/a)
(iv) Area under the impulse function is equal to one.
∫_(-∞)^∞▒〖δ(t)〗dt = 1
(v) Time Reversal
𝛿(-t) = 𝛿(t)

S5. Ans. (c)
Sol. The output of AND gate is HIGH only when all the inputs of the AND gate is HIGH.

S6. Ans.(a)
Sol. In Sign magnitude number, if maximum bit is ‘1’ then it indicates a negative number and if ‘0’ then it indicates a positive number.

S7. Ans.(d)
Sol. Local area network can transmit faster than telecommunications over public telephone lines because they uses twisted pair wiring or coaxial cable. These wires have faster data transmission rate.

S8. Ans (d)
Sol. Given:
V_max = 390 V
V_min = 260 V
Now,
SWR = V_max/V_min
⇒ SWR = 390/260
So, SWR = 1.5

S9. Ans.(a)
Sol. Resistance of a conductor is
R=ρ l/a
where,
ρ is specific resistivity
l is length of the conductor
A is cross-sectional area.

S10. Ans.(d)
Sol As there is no initial charge on the capacitor so voltage across the capacitor is zero.
We know that current flowing in the capacitor is
⇒ I = CdV/dt
So, I = 0
No current is flowing through the capacitor, hence it acts as an Open Circuit.

Quiz Electronics Engineering 15 Sep 2020

Quiz Electronics Engineering
Exam: NIC
Topic: Miscellaneous
Date: 15/09/2020

Each Question carries 1 Mark
Negative Marking: 1/4
Time: 10 Minutes

Q1. The circuit in which conductors are connected end to end so that same current flows through each is called a
(a) parallel circuit
(b) simple circuit
(c) series circuit
(d) none of these

Q2. What is WPA?
(a) wi-fi protected access
(b) wired process access
(c) wired protected access
(d) wi-fi process access

Q3. Consider a discrete random variable assuming finitely many values. The cumulative distribution function of such a random variable is
(a) non-increasing function
(b) non-decreasing function assuming values larger than one
(c) non-decreasing function without discontinuity
(d) non-decreasing function with finitely many discontinuity and assuming values less than one

Q4. MOV [BX], AL type of data addressing is called
(a) Register addressing
(b) Immediate addressing
(c) Register relative
(d) Register indirect addressing

Q5. The unit of conductivity is
(a) ohm/m
(b) mho/m
(c) ohm. m
(d) mho. m

Q6. I_CB0 in a transistor can be reduced by reducing:
(a) Temperature
(b) V_CC
(c) I_E
(d) I_B

Q7. If maximum and minimum voltages on a transmission line are 4 V and 2 V respectively, VSWR is
(a) 0.5
(b) 1
(c) 2
(d) 8

Q8. The Nyquist sampling interval, for the signal sin𝑐(700 𝑡) + sin𝑐(500 𝑡) is
(a) 1/350 𝑠𝑒𝑐
(b) 1/700𝑠𝑒𝑐
(c) π/350 𝑠𝑒𝑐
(d) π/175 𝑠𝑒𝑐

Q9. The use of multiple register windows with overlap causes a reduction in the number of memory accesses for
1. Function locals and parameters
2. Register saves and restores
3. Instruction fetches
(a) 2 only
(b) 3 only
(c) 1 only
(d) 1, 2 and 3

Q10. Which of the following is a Self-Complementing code?
(a) 8421 Code
(b) Excess-3 Code
(c) Pure binary code
(d) Gray Code

SOLUTIONS

S1. Ans.(c)
Sol. When same current flows through all conductors of a circuit then all conductors are connected in series. This type of circuit called a Series circuit.

S2. Ans.(a)
Sol. WPA stands for Wi-Fi protected access and used to secure wireless computer networks. It provides data encryption and better user authentication than Wired Equivalent Privacy (WEP).

S3. Ans.(d)
Sol. The Cumulative Distribution Function of a discrete time random variable is always less than 1. It may have constant value or any increasing function i.e. non-decreasing function.

S4. Ans.(d)
Sol.
Immediate addressing mode:- Operand is directly written in the instruction itself. Instructions are longer. E.g. MOV AL, 20H.
Register addressing mode:- Operands are stored in the registers and that register is written in the instruction. The instructions are compact and fastest of all. e.g. MOV AX, BX.
Register indirect addressing mode:- The effective address of the memory may be taken directly from one of the base register or index register specified by instruction. If register is SI, DI and BX then DS is by default segment register. If BP is used, then SS is by default segment register. e.g. MOV CX, [BX]. So, [BX] refers to the memory location which is written in the register BX. Hence, it can be said that it is register Indirect Addressing Mode.
Register relative addressing mode:- The operand address is calculated using one of the base registers and an 8 bit or a 16 bit displacement. e.g. MOV CL, [BX + 04H]

S5. Ans.(b)
Sol.
⇒ Conductivity = 1/Resistivity=1/(ohm.m)
Hence, unit of conductivity is mho/m.

S6. Ans.(a)
Sol. I_CB0 is a current which flows in the transistor when emitter-base junction is Open circuit. I_CB0 is a minority carrier current and we know that minority carrier currents are dependent on the temperature. So to reduce I_CB0 temperature must be reduced.

S7. Ans.(c)
Sol. Given:
V_max = 4 V
V_min = 2 V

We know that,
VSWR = V_max/V_min
So, VSWR = 4/2 = 2

S8. Ans.(b)
Sol. Given Signal is:-
⇒ sin𝑐(700 𝑡) + sin𝑐(500 𝑡) = (sin⁡(700πt))/700πt + (sin⁡(500πt))/500πt

The maximum frequency component is
2πfm = 700π
⇒ 2πfm = 700π
∴ fm = 350 Hz

The Nyquist rate is
fs = 2fm
So, fs = 2 x 350 Hz = 700 Hz
Hence, Sampling interval (1/f_s ) = 1/700 sec

S9. Ans.(c)
Sol. The use of multiple register window eliminates the need to access the variable repeatedly from the memory. It is stored in registers causing a reduction in number of memory access for function locals and parameters. We still save data in memory and uses instruction fetch for fetching instruction.

S10. Ans.(b)
Sol. Out of the given options only in case of Excess-3 code the 9’s complement code of the decimal number is easily obtained by changing 1’s to 0’s and 0’s to 1’s. So, Excess-3 code is a Self-complementing code.

Quiz Electronics Engineering 14 Sep 2020

Quiz Electronics Engineering
Exam: NIC
Topic: Miscellaneous
Date: 14/09/2020

Each Question carries 1 Mark
Negative Marking: 1/4
Time: 10 Minutes

Q1. For a n-channel FET, What is the direction of current flow?
(a) Source to drain
(b) Gate to source
(c) Drain to source
(d) Gate to drain

 

Q2. 16 bit microprocessor has memory:
(a) 1 MB
(b) 64 KB
(c) 256 Byte
(d) 2MB

 

Q3. In binary data transmission DPSK is preferred to PSK because
(a) more protection is provided against impulse noise
(b) for a given energy per bit, the probability of error is less
(c) the 180o phase shift of the carrier are unimportant
(d) a coherent carrier is not required to be generated at the receiver

 

Q4. Assertion(A): A linear system gives a bounded output if the input is bounded.
Reason(R): The roots of the characteristics equation have all negative real parts and response due to initial conditions decay as time t tends to infinity.
(a) Both A and R are True and R is the correct explanation of A.
(b) Both A and R are True but R is not the correct explanation of A.
(c) A is True but R is False.
(d) A is False but R is True.

 

Q5. By what name is the equation ∇.J ⃗ = 0 frequently known?
(a) Poisson’s equation
(b) Laplace equation
(c) Continuity equation for steady currents
(d) Displacement equation

 

Q6. Which of the following is called as primary or main memory?
(a) RAM
(b) Memory stick
(c) Hard disk
(d) Flash memory

 

Q7. Any set of Boolean operators that is sufficient to represent all Boolean expressions is said to be complete. Which of the following is not complete?
(a) {NOT, OR}
(b) {AND, OR}
(c) {NOR}
(d) {AND, NOT}

 

Q8. Which media access control protocol is used by IEEE 802.11 wireless LAN?
(a) CDMA
(b) ALOHA
(c) CSMA/CA
(d) None of these

 

Q9. Assertion(A): In the exponential Fourier representation of a real-valued periodic function f(t) of frequency f_o the coefficients of the terms e^(-j2πnf_o t) and e^(j2πnf_o t) are negatives of each other.
Reason(R): The discrete magnitude spectrum of f(t) is even and the phase spectrum is odd.
(a) Both A and R are True and R is the correct explanation of A.
(b) Both A and R are True but R is not the correct explanation of A.
(c) A is True but R is False.
(d) A is False but R is True.

 

Q10. The magnetic flux density and the vector magnetic potential A are related as
(a) B ⃗ = ∇ . A ⃗
(b) A ⃗ = ∇ × B ⃗
(c) B ⃗ = ∇ × A ⃗
(d) A ⃗ = ∇ . B ⃗

 

 

SOLUTIONS

 

S1. Ans.(c)
Sol. In a n-channel FET electrons are majority carriers so current flows in opposite direction to the flow of electron. When supply voltage is applied across Drain & source, electrons in n-channel flow from Source to drain and current from Drain to source.

S2. Ans.(b)
Sol. 16 bit microprocessor has 216 byte memory i.e., 64KB.
⇒ 216 B = 210+6 B = 26 KB = 64 KB

S3. Ans.(d)
Sol. In binary data transmission DPSK is preferred to PSK because a coherent carrier is not required to be generated at the receiver.

S4. Ans.(a)

S5. Ans.(c)
Sol. For steady current (dρ_v)/dt=0
So, Continuity equation becomes ∇.J ⃗ = 0

S6. Ans.(a)
Sol. RAM(Random Access Memory) is called as primary or main memory. The RAM is more faster than other secondary memory like Flash memory, Hard disk, Memory stick etc. The access time of any data from any location within RAM is same. The read and write time taken for any data from memory does not depend on the physical location.

S7. Ans.(b)
Sol. The universal gates are NAND and NOR. Both can represent all other logic gate.
So, considering each option.
NOT and OR combines for NOR GATE
itself NOR GATE
Combining AND & OR we can’t achieve all logic gate.
AND & OR corresponds to NAND GATE.

S8. Ans.(c)
Sol. IEEE 802.11 wireless LAN uses Carrier Sense Multiple Access Protocol with Collision Avoidance (CSMA/CA) as media access control protocol.

S9. Ans.(a)

S10. Ans.(c)

Quiz Electronics Engineering 11 Sep 2020

Quiz Electronics Engineering
Exam: NIC
Topic: Miscellaneous
Date: 11/09/2020

Each Question carries 1 Mark
Negative Marking: 1/4
Time: 10 Minutes

Q1. A charge ‘Q’ is divided between two point charges. What should be the values of this charge on the objects so that the force between them is maximum?
(a) Q/3
(b) 2Q
(c) (Q -2)
(d) Q/2

Q2. The correct sequence of subsystems in an FM receiver is
(a) mixer, RF amplifier, limiter, IF amplifier, discriminator, audio amplifier
(b) RF amplifier, mixer, IF amplifier, limiter, discriminator, audio amplifier
(c) RF amplifier, mixer, limiter, discriminator, IF amplifier, audio amplifier
(d) mixer, IF amplifier, limiter, audio amplifier, discriminator

Q3. Conductors have
(a) positive temperature coefficient of resistance
(b) Negative temperature coefficient of resistance
(c) low temperature coefficient of resistance
(d) none of these

Q4. What addressing mode is used in the instruction RET?
(a) Direct
(b) Register-Indirect
(c) Immediate
(d) Implicit

Q5. DHCP provides __________ to the client.
(a) URL
(b) MAC address
(c) IP address
(d) None of the above

Q6. Match List-I(Laws) with List-II(Applications) and select the correct answer using codes given below the lists:
List-I List-II
A. Ampere’s law 1. To find force on a charge.
B. Biot’s Law 2. To find force due to a current element.
C. Coulomb’s Law 3. To find electric flux density at a point.
D. Gauss’s Law 4. To find magnetic flux density at a point.
Codes:
A B C D
(a) 3 2 1 4
(b) 3 1 2 4
(c) 4 1 2 3
(d) 4 2 1 3

Q7. Which of the following transistor is affected by static electricity?
(a) MOSFET
(b) JFET
(c) UJT
(d) NPN transistor

Q8. IPsec is designed to provide security at the _________
(a) Transport layer
(b) Application layer
(c) Network layer
(d) Session layer

Q9. The number of comparator required for flash type A/D converter
(a) Triples for each added bit
(b) Reduce by half for each added bit
(c) Double for each added bit
(d) Doubles exponentially for each added bit

Q10. Discrete-time version of unit impulse is defined as ______
(a) 𝛿(n) = {█(1; n=0@0 ; n≠0)┤
(b) 𝛿(n) = 1 for all value of n
(c) (n) = {█(A; n=0@0 ; n≠0)┤
(d) 𝛿(n) = {█(1; n≠0@0 ; n=0)┤

SOLUTIONS

S1. Ans.(d)
Sol. From coulomb’s Law, we get
F = (KQ_1 Q_2)/r^2
The force will be maximum when both the charges are equally divided so that their product becomes maximum.

S2. Ans.(b)
Sol. Block diagram of FM Receiver:-

S3. Ans.(a)
Sol. Conductors have positive temperature coefficient of resistance because resistance increases with the increase in temperature in conductor.

S4. Ans.(b)
Sol. ‘RET’ means Return from subroutine unconditionally. The execution of instruction is transferred from subroutine part to the next step from where subroutine was called. This is done with the help of POP opcode so that program counter can be loaded with that address.
It is in Register-Indirect addressing mode because the location of the register where operand is present is mentioned with the help of address.

S5. Ans.(c)
Sol. Dynamic Host Configuration Protocol (DHCP) is a network management protocol used to automate the process of configuring devices on IP networks. DHCP server dynamically assigns an IP address and other network configuration parameters to each device on the network. The hosts know about the change dynamically and update their info themselves. It is used for both IPv4 and IPv6 addressing.

S6. Ans.(d)

S7. Ans.(a)
Sol. All MOSFET is sensitive to static electricity. If static electricity is applied to the gate at the time of mounting the board, the gate oxide layer may be destroyed.

S8. Ans.(c)
Sol. IPsec(Internet Protocol Security) is a set of protocols used to provide authentication, data integrity and confidentiality between two machines in an IP network. In the TCP/IP model, it provides security at the IP layer i.e. the Network Access Layer.

S9. Ans.(c)
Sol. The minimum number of comparators needed for n-bit conversion = 2^n-1
So, We can say that the number of comparator required almost doubles for each added bit. For example: – A 2 -bit ADC requires three comparators, 3 -bit ADC needs seven comparators and so on.

S10. Ans.(a)
Sol. Discrete Unit Impulse function is an elementary signal with value 1 at n = 0 only.

Quiz Electronics Engineering 8 Sep 2020

Quiz Electronics Engineering
Exam: NIC
Topic: Miscellaneous
Date: 08/09/2020

Each Question carries 1 Mark
Negative Marking: 1/4
Time: 10 Minutes

Q1. Match List-I with List-II and select the correct answer using the codes given below the lists:
List-I List-II
A. SSB 1. Envelope detector
B. AM 2. Integrate and dumb
C. BPSK 3. Hilbert Transform
4. Ratio detector
5. PLL
Codes:
A B C
(a) 3 1 2
(b) 3 2 1
(c) 2 1 3
(d) 1 2 3

Q2. Consider the following statements:
Plane wave propagation through a circular waveguide results in
1. TE modes
2. TM modes
Which of the above statements is/are correct?
(a) 1 only
(b) 2 only
(c) both 1 or 2
(d) either 1 and 2

Q3. Ready pin of a microprocessor is used: –
(a) to indicate that microprocessor is ready to receive input.
(b) to introduce wait states.
(c) to indicate that microprocessor is ready to receive output.
(d) to provide direct memory access

Q4. Result of subtraction of binary number 0101 from the binary number 1110 will be
(a) 0101
(b) 1001
(c) 1100
(d) None of these

Q5. If a system produces frequencies in the output that are not present in the input, then the system cannot be
(a) Minimum Phase System
(b) Stable and Linear
(c) Stable and Causal
(d) Linear Shift Invariant

Q6. IEEE 802.11 is standard for
(a) Wireless LANs
(b) Ethernet
(c) Bluetooth
(d) Broadband wireless

Q7. Clock speed of a 8085 microprocessor is:
(a) 5 MHz
(b) 10 MHz
(c) 80 MHz
(d) 3 MHz

Q8. While calculating R_Th , constant current sources in the circuit are?
(a) replaced by opens
(b) replaced by shorts
(c) treated in parallel with other voltage sources
(d) converted into equivalent voltage sources

Q9. What does the expression ½ J ⃗. A ⃗ represent?
(a) Electric energy density
(b) Radiation resistance
(c) Power density
(d) Magnetic energy density

Q10. Which of the following material finds application in light emitting diodes?
(a) Silicon
(b) Phosphorous
(c) Sulphur
(d) Gallium phosphide

SOLUTIONS

S1. Ans.(a)
Sol.
SSB → Hilbert Transform
AM → Envelope detector
BPSK → Integrator and dumb

S2. Ans.(c)
Sol. Circular Waveguide supports both Transverse Electric (TE) and Transverse Magnetic (TM) modes.

S3. Ans.(c)
Sol. READY signal is used to interface with the slower peripheral devices(Memory or I/O devices) to the microprocessor. If Ready signal is ‘HIGH’ then peripheral devices can transfer data but if Ready Signal is ‘LOW’ then peripheral device can’t transfer data. It waits for signal to become ‘HIGH’.

S4. Ans(b)
Sol. Convert both binary number to decimal and then do the subtraction and again convert back to binary number.
Step 1: Binary to decimal
⇒ 11102 = 1410
⇒ 01012 = 510
Step 2: Do subtraction
⇒ 14 – 5 = 9
Step 3: Convert back to binary number
⇒ 910 = 10012
⇒ 1110 – 0101 = 1001

S5. Ans.(d)
Sol. If a system producing frequencies in the output that are present in the input then the system is Linear Shift Invariant but if there is no presence of frequency in the input and output produces frequency then system cannot be Linear Shift Invariant.

S6. Ans.(a)

S7. Ans.(d)

S8. Ans.(a)

S9. Ans.(d)
Sol. Magnetic Energy Density is
(dW_H)/dv = 1/2 B ⃗. H ⃗ = 1/2 J ⃗. A ⃗ = 1/2µH^2

S10. Ans.(d)

Quiz Electronics Engineering 7 Sep 2020

Quiz Electronics Engineering
Exam: NIC
Topic: Miscellaneous
Date: 07/09/2020

Each Question carries 1 Mark
Negative Marking: 1/4
Time: 10 Minutes

Q1. A unit impulse function 𝛿(t) is defined by
1. 𝛿(t) = 0 for all t except t = 0
2. ∫_(-∞)^∞▒〖δ(t)〗dt = 1
The Fourier Transform F(ω) of 𝛿(t) is
(a) 1
(b) 1/ω
(c) 0
(d) 1/jω

Q2. The electrical systems which operate at two discrete voltage levels is knows as ……… system.
(a) hybrid
(b) digital
(c) analog
(d) none of the above.

Q3. The number of valence electrons in pentavalent impurity is:
(a) 3
(b) 4
(c) 5
(d) 1

Q4. The synchronization between microprocessor and memory is done by –
(a) READY signal
(b) ALE signal
(c) HOLD signal
(d) None of the above

Q5. When the phase velocity of an electromagnetic wave depends on frequency in any medium, the phenomenon is called
(a) Scattering
(b) polarization
(c) absorption
(d) dispersion

Q6. In a PCM system with uniform quantization, increasing the number of bits from 8 to 9 will reduce the quantization noise power by a factor of
(a) 9
(b) 8
(c) 4
(d) 2

Q7. What is loopback address ?
(a) 127.0.0.1
(b) 255.0.0.0
(c) 255.255.0.0
(d) 127.0.0.0

Q8. An input/output device at which data enters or leaves a computer system is:
(a) keyboard
(b) plotter
(c) printer
(d) terminal

Q9. Due to which of the following reasons a NAND gate is called a Universal logic element?
(a) Many digital computers use NAND gates
(b) All the minimizing techniques are applicable for optimum NAND gate realization
(c) Any logic function can be realized by NAND gate alone
(d) All of the above

Q10. For Half-wave(odd) symmetry, with T_o = period of x(t), which one of the following is correct?
(a) x(t ± T_o/2) = -x(t)
(b) x(t ± T_o/2) = -x(t)
(c) x(t ± T_o) = -x(t)
(d) x(t ± T_o) = x(t)

SOLUTIONS

S1. Ans.(a)
Sol. Fourier Transform is –
𝛿(t) □(↔┴( F.T ) ) 1

S2. Ans.(b)
Sol. The electrical systems which operate at two discrete voltage levels either at High Voltage level or Low Voltage level is known as Digital System.

S3. Ans. (c)
Sol. Valence electron are electrons located in the outermost shell of an atom.

S4. Ans.(a)
Sol. READY signal is used to interface with the slower peripheral devices(Memory or I/O devices) to the microprocessor.

S5. Ans.(b)

S6. Ans.(c)
Sol. We know that, Quantization noise in PCM is given by
⇒ NQ = Δ^2/12
where,
Δ = (Dynamic range)/L = V_(P-P )/2^n
Now,
NQ = V_(P-P)^212 x 22n
⇒ N_Q ∝ ( 1)/( 2^2n )
For n = 8,
⇒ 〖N_Q〗_1 ∝ ( 1)/( 2^(2 x 8) ) = ( 1)/( 2^16 )
For n = 9,
⇒ 〖N_Q〗_2 ∝ ( 1)/( 2^(2 x 9) ) = ( 1)/( 2^18 )
and (〖N_Q〗_2 )/(〖N_Q〗_1 ) = (( 1)/( 2^18 ))/(( 1)/( 2^16 )) = 2^16/2^18 = 1/4
So, 〖N_Q〗_2 = (〖N_Q〗_1 )/4

S7. Ans.(a)
Sol. 127.0.0.1 is the loopback IP address. It is used to test the communication or transportation medium on a local network card or for testing network applications. Data packets sent on a loopback address are re-routed back to the originating node without any alteration or modification. It is a communication channel with only one endpoint. TCP/IP networks specify a loopback that allows client software to communicate with server software on the same computer.

S8. Ans.(c)

S9. Ans.(b)
Sol. A NAND gate is called a Universal logic element because all the minimizing techniques are applicable for optimum NAND gate realization. We can implement any logic circuit using the NAND gate.

S10. Ans.(a)
Sol. For Odd half-wave symmetry –
x(t) = -x(t±T_o/2)

Quiz Electronics Engineering 5 Sep 2020

Quiz Electronics Engineering
Exam: NIC
Topic: Miscellaneous
Date: 05/09/2020

Each Question carries 1 Mark
Negative Marking: 1/4
Time: 10 Minutes

Q1. How many layers are present in the TCP/IP model?
(a) 5
(b) 7
(c) 6
(d) 10

Q2. Two thin parallel wires are carrying current along the same direction. The force experienced by one due to the other is
(a) parallel to the lines.
(b) perpendicular to the lines and repulsive.
(c) perpendicular to the lines and attractive.
(d) zero.

Q3. In a broadcast communication receiver, most of the receiver selectivity is achieved in:
(a) RF section
(b) IF section
(c) Mixer
(d) Local oscillator

Q4. The microprocessor uses the _______ register to sequence the execution of the instruction.
(a) stack pointer
(b) program counter
(c) instruction pointer
(d) accumulator

Q5. FET is advantageous in comparison with BJT because of
(a) high input impedance
(b) high gain-bandwidth product
(c) its current controlled behaviour
(d) high noise immunity

Q6. Voltage drop across 25 Ω resistor

(a) 60 V
(b) 240 V
(c) 400 V
(d) 100 V

Q7. Given the decimal number 19, an eight bit two’s complement representation is given by
(a) 11101110
(b) 11101101
(c) 11101100
(d) None of these

Q8. Which one of the following is the correct relation?
(a) F(at) ⟷ aF(ω/a)
(b) F(at) ⟷ aF(aω)
(c) F(t/a) ⟷ aF(ω/a)
(d) F(at) ⟷ (1/a)F(ω/a)

Q9. Radiation intensity does not depend upon
(a) the antenna direction
(b) distance from the radiator
(c) both (a) and (b) above
(d) none of the above

Q10. When a program assigns 8 bits to a pixel, that pixel can display one of up to ____________ colors.
(a) 32
(b) 64
(c) 256
(d) 1024

SOLUTIONS

S1. Ans.(a)
Sol. There are 5 layers in the TCP/IP model. Those are – Application Layer, Transport Layer, Internet Layer and Network Access Layer. The TCP/IP model is also called as Internet Protocol Stack model.

S2. Ans.(c)
Sol. Force is always perpendicular to the current carrying line and Force will be attractive if both the current carrying wire have same direction of flow of current and repulsive if current flow in both wire in opposite direction.

S3. Ans. (a)
Sol. In a broadcast communication receiver, most of the receiver selectivity is achieved in RF stage.

S4. Ans.(b)
Sol. Program Counter is used to sequence the execution of the instruction. It stores the address of the next instruction and changes after execution of that instruction. This process continues in a sequence.

S5. Ans.(a)
Sol. Advantages of FET: –
high input impedance
low output impedance
low noise level
excellent buffer amplifier

S6. Ans.(d)
Sol. All resistors are connected in series so same current will flow in all resistance.
Net resistance is 100 Ω.
Current flowing is
I=400/100 = 4A
Hence, Voltage drop across 25 Ω resistor = 25 × 4 = 100 V

S7. Ans(b)
Sol.
Step 1: Convert 19 to binary number
The binary representation of + 19 in 8-bit is 00010011.
Step 2: Take the compliment of given number.
Complement of 0001 0011 is 1110 1100
Step 3: Add 1 to the complemented number.
1110 1100 + 1 = 1110 1101

Therefore, An 8-bit 2’s complement representation of 19 is 1110 1101.

S8. Ans.(d)
Sol. In Time Scaling property of Fourier Transform, we get
x(at) ↔┴( F.T ) 1/|a| X(ω/a)

S9. Ans.(b)
Sol. Radiation intensity does not depend upon distance from the radiator

S10. Ans.(c)
Sol. Maximum number of colors = 2^n
where,
n is number of bits or pixel
Hence, Number of color in 8-bits = 2^8 = 256

Quiz Electronics Engineering 4 Sep 2020

Quiz Electronics Engineering
Exam: NIC
Topic: Miscellaneous
Date: 04/09/2020

Each Question carries 1 Mark
Negative Marking: 1/4
Time: 10 Minutes

Q1. The energy gap between valance band and conduction band is
(a) 1 eV
(b) 7 eV
(c) 0.1 eV
(d) 0.7 eV

Q2. Poisson’s equation is derived with the following assumption about the medium. The medium is
(a) Non-homogeneous and isotropic
(b) Non-homogeneous and non-isotropic
(c) homogeneous and non-isotropic
(d) homogeneous and isotropic

Q3. To multiply a number by 8 in 8085 we have to use RAL instruction –
(a) Once
(b) Twice
(c) Thrice
(d) Four times

Q4. The diagonal clipping in Amplitude Modulation(using Envelope detector) can be avoided if RC time constant of the envelope detector satisfies the following condition, (here W is the message bandwidth and ω is carrier frequency both in rad/sec)
(a) RC = 1/ω
(b) RC > 1/W
(c) RC < 1/ω
(d) RC < 1/W

Q5. The value of current at resonance in series RLC circuit is affected by the value of
(a) R
(b) L
(c) C
(d) none of the above

Q6. The function of presentation layer is to __________.
(a) Validate and establish connection
(b) Encrypt data
(c) Close the session
(d) Flow Control

Q7. The covariance function of a band limited white noise is
(a) A Dirac delta function
(b) An exponentially decreasing function
(c) a sinc function
(d) a sinc^2 function

Q8. In Boolean algebra, (X+ Y).(X+Z) is equal to
(a) X+YZ
(b) Y+XZ
(c) XY+Z
(d) XZ+Y

Q9. Consider the following:
1. Electric current flowing in a conducting wire.
2. A moving charged belt.
3. An electron beam in a cathode ray tube.
4. Electron movement in a vacuum tube.
Which of the above are examples of convection current?
(a) 1, 2, 3 and 4
(b) 1, 2 and 4
(c) 1 and 3
(d) 2, 3 and 4

Q10. Microprogramming refers to
(a) the use of storage to implement the control unit
(b) programming at micro level
(c) emulation
(d) array processing

SOLUTIONS

S1. Ans.(a)
Sol. A semiconductor material has almost filled valence band and nearly empty conduction band with a very small energy gap (≃ 1 eV) between them.

S2. Ans.(d)

S3. Ans.(c)
Sol. ‘RAL’ means each binary bit of the accumulator is rotated left by one position through the carry flag. The D_7 bit data is placed in carry flag and data of carry flag is placed in D_0 bit.
In 8085 microprocessor, to multiply any number by 8 we have to use RAL instruction thrice.

S4. Ans.(d)
Sol. For proper envelope detection and to avoid diagonal clipping, RLC should be
1/f_c < RLC < 1/f_m
Therefore, 1/ω < RC < 1/W

S5. Ans (a)
Sol. At resonance, the net reactance is zero. The reactance effect of both inductor and capacitor is cancelled out. So, net impedance is resistive only. Hence, The value of current at resonance in series RLC circuit is due to resistance only.
Current(I) = V/R

S6. Ans.(b)
Sol. The Presentation layer is present at the sixth position in the OSI(Open Systems Interconnection) model. It helps the application layer in delivery and formatting of information for further processing or display. It does all the work related to data presentation and transport, including translation, encryption, and compression.
Functions:-
Network security and confidentiality management, text compression and packaging.
Syntax conversion, code conversion, character conversion, data format modification, data compression, encryption.
Grammar negotiation
Connection management

S7. Ans.(c)
Sol. Band limited noise is a rectangular function. So, covariance function is a sinc function.

S8. Ans.(a)
Sol. Expansion Rule is
(X+ Y)(X + Z) = XX+ XZ + XY + YZ [XX = X]
= X(1+Z) + XY+ YZ = X + XY + YZ [1+Z=1 X.1= X]
= X(1 + Y) + YZ = X+ YZ

S9. Ans.(d)
Sol.
A convection current is a process which involves the movement of energy from one place to another.
Conduction current is the electric current which exists in a conductor when the electrons flow in the conductor at a uniform rate.

S10. Ans.(c)
Sol. Microprogramming consists of microcode with the help of which large number of architectures are achieved. It consists of large number of execution units and wider word lengths.

Quiz Electronics Engineering 3 Sep 2020

Quiz Electronics Engineering
Exam: NIC
Topic: Miscellaneous
Date: 03/09/2020

Each Question carries 1 Mark
Negative Marking: 1/4
Time: 10 Minutes

Q1. When transistors are used in digital circuits they usually operate in the
(a) active region
(b) break down region
(c) saturated region
(d) saturation and cut off region

Q2. A fetch cycle is the:
(a) First part of the instruction cycle
(b) Last part of the instruction cycle
(c) Intermediate part of the instruction
(d) Auxiliary part of the instruction cycle

Q3. The term “White Noise” refers to the following:
(a) A random signal generated by beat signal
(b) A random signal with flat Power Spectral Density
(c) A random signal with long range correlation
(d) All of the above are true

Q4. The units of the spectrum obtained by Fourier transforming the covariance function of a stationary stochastic process is
(a) power per second
(b) energy per Hertz
(c) power per Hertz
(d) energy per second

Q5. The efficiency of Zener Diode for heavy load current is
(a) Low
(b) zero
(c) very low
(d) Infinity

Q6. Consider the following statements regarding smith charts:
(1) A normalized smith chart applies to a line of any characteristic resistance and serves as well for normalized admittance
(2) A polar co-ordinate smith chart contains circles of constant |Z| and circles of constant ∠Z.
(3) in Smith chart, the distance towards the load is always measured in clockwise direction.
Which of the statements given above are correct?
(a) 1, 2 and 3
(b) 2 and 3
(c) 1 and 3
(d) 1 and 2

Q7. Advanced Encryption Standard (AES) is based on
(a) Asymmetric key algorithm
(b) Symmetric key algorithm
(c) Public key algorithm
(d) Key exchange

Q8. What is the Laplace Transform of cosωt?
(a) ω/〖(s+ω)〗^2
(b) ω/(s^2+ω^2 )
(c) s/(s^2+ω^2 )
(d) s/〖(s+ω)〗^2

Q9. Instruction LHLD 2000H is an example of:
(a) Implied addressing
(b) Direct addressing
(c) Indirect addressing
(d) Register addressing

Q10. Power factor can be improved by
(a) by using transition
(b) by using R-L circuit
(c) by using synchronous motor
(d) None of these

SOLUTIONS

S1. Ans. (d)
Sol. When transistors are used in digital circuits they usually operate in the saturation and cut off region. In Saturation region they act as a Short Circuit i.e., ON(‘1’) and in Cut-off region they act as Open Circuit i.e., OFF(‘0’).

S2. Ans.(a)
Sol. Instruction Cycle consists of fetch cycle and execute cycle. So, A fetch cycle is the first part of the instruction cycle.

S3. Ans.(b)
Sol.

S4. Ans.(c)

S5. Ans.(a)
Sol. In Zener diode, current is limited only by the external resistance and the power dissipation of Zener diode so for heavy load current power dissipation goes high hence it will result low efficiency of the Zener diode.

S6. Ans.(d)
Sol. In Smith Chart, the distance towards the load is always measured in anti-clockwise direction.

S7. Ans.(b)
Sol: Advanced encryption standard (AES) is used in symmetric key algorithm for the encryption of electronic data. It is an iterative rather than Feistel cipher. It is based on ‘substitution–permutation network’ and comprises of a series of linked operations.

S8. Ans.(c)

S9. Ans.(b)
Sol. ‘LHLD 2000H’ is in Direct Addressing Mode. It means data stored in the location 2000 H is loaded in ‘HL register pair’. It is a 16-bit address with 3 byte instructions.

S10. Ans.(c)
Sol. A synchronous motor under over-excited condition operates at a leading power factor. Synchronous motors are therefore employed in large power installations for improving the overall power factor of the installation.

Quiz Electronics Engineering 1 Sep 2020

Quiz Electronics Engineering
Exam: NIC
Topic: Miscellaneous
Date: 01/09/2020

Each Question carries 1 Mark
Negative Marking: 1/4
Time: 10 Minutes

Q1. Why MOSFET is preferred over BJT in IC components?
(a) MOSFET has low packing density
(b) MOSFET has medium packing density
(c) MOSFET has high packing density
(d) MOSFET has no packing density

Q2. The maximum power that a 12 Volts DC source with an internal resistance of 2Ω can supply to a resistive load is
(a) 12 W
(b) 18 W
(c) 36 W
(d) 48 W

Q3. What instruction in an 8085 processor can set a flag?
(a) STA 2000 H
(b) JNZ 2100H
(c) ADD B
(d) MOV B, C

Q4. What is the inverse Laplace Transform of e^(-sa)/s ?
(a) e^(-at)
(b) (t – a)u(t – a)
(c) 𝛿(t – a)
(d) u(t – a)

Q5. In communication systems, noise due to quantization error is
(a) Linear and signal dependent
(b) Non-linear and signal dependent
(c) Linear and signal independent at low frequencies only
(d) Non-linear and signal dependent at low frequencies only

Q6. What is routing algorithm used by OSPF routing protocol?
(a) Distance vector
(b) Flooding
(c) Path vector
(d) Link state

Q7. Hysteresis loss cannot occur in
(a) magnetic material
(b) Insulating material
(c) non-magnetic material
(d) none of these

Q8. In 8085 microprocessor, after the execution of XRA A instruction: –
(a) The carry flag is set
(b) The zero flag is set.
(c) The accumulator contains FFH.
(d) The accumulator contents are shifted left by one bit

Q9. An AND gate is a …. Circuit.
(a) relaxation
(b) memory
(c) sequential
(d) combinational

Q10. The wavelength of a wave with propagation constant (0.1π + j0.2π )m-1 is
(a) 2/√0.05 m
(b) 30 m
(c) 20 m
(d) 10 m

SOLUTIONS

S1. Ans.(a)
Sol. MOSFET is preferred over BJT because of its low packaging density. Due to low packaging density, more number of MOSFET memory cells can be accommodated in a particular area. It will require less percentage of chip area as compared to BJT.

S2. Ans.(b)
Sol. Given:
V = 12 volts
R = 2Ω
According to Maximum Power Transfer Theorem,
⇒ P = V^2/4R
⇒ P = (12 ×12)/(4 ×2)
So, P = 18 W

S3. Ans.(c)
Sol. Only ADD B can set the flag in an 8085 microprocessor. It will set the Carry Flag.

S4. Ans.(d)
Sol. We know that,
u(t) ↔┴( L.T ) 1/s
f(t-a) ↔┴( L.T ) e^(-sa)F(s)
So, Laplace Transform of e^(-sa)/s is obtained from the signal
⇒ u(t – a) ↔┴( L.T ) e^(-sa).1/s

S5. Ans.(a)
Sol. We know that, Maximum quantization error
⇒ [Qe]max = ±Δ/2 = Sampled Value – Quantized Value
So, [Qe]max =m(t)-m_q (t)
where,
m(t)→ Original message signal
m_q (t)→ quantized signal
Therefore, Noise due to quantization error is linear and is dependent on the message signal.

S6. Ans.(d)
Sol. Open Shortest Path First (OSPF) routing protocol uses a Link State Routing (LSR) algorithm. OSPF forms IP datagrams directly instead of carrying data via a transport protocol, UDP or TCP like other routing protocol.

S7. Ans.(c)
Sol. Hysteresis loss is related to the magnetic flux density. So, it cannot occur in non-magnetic material.

S8. Ans.(b)
Sol. ‘XRA’ means Exclusive OR operation is applied between the contents of the accumulator and the contents of the operand i.e. register or memory. The result is stored in the accumulator.
Here, Ex-OR operation is applied between the contents of the accumulator only. We know that if the inputs are same then the output of the Ex-OR operation will be zero. So, the final result is ‘0’ in the accumulator i.e. Zero flag is set as accumulator is empty.

S9. Ans (d)
Sol. Combinational circuits are defined as the time independent circuits which do not depend upon previous inputs to generate any output.

S10. Ans.(d)
Sol. We know Propagation constant is
⇒ γ = α + jβ = 0.1π + j0.2π
and β = 2π/λ
Comparing real and imaginary part, we get
⇒ β = 0.2π = 2π/λ
So, λ = 2π/0.2π = 10m

Quiz Electronics Engineering 31 Aug 2020

Quiz Electronics Engineering
Exam: NIC
Topic: Miscellaneous
Date: 31/08/2020

Each Question carries 1 Mark
Negative Marking: 1/4
Time: 10 Minutes

Q1. In order to improve power factor, we can connect a ____________ in parallel with load,
(a) Capacitor
(b) Resistance
(c) Inductor
(d) None of these

Q2. Physical or logical arrangement of network is __________
(a) Control
(b) Topology
(c) Networking
(d) Routing

Q3. Which of the following semiconductor materials is are used for manufacturing solar cells?
(a) Gallium arsenide
(b) Indium arsenide
(c) Cadmium sulphide
(d) All of these

Q4. Which one of the following statements is correct?
Digital modulation techniques are used in satellite communication systems because:
(a) They are less prone to interference
(b) Large bandwidth utilization is possible
(c) They have a higher spectral efficiency
(d) They are easier to handle

Q5. Consider an LTI system representing a passive electrical network. If the input is a sinusoidal signal, then the steady state output of the network is
(a) sinusoidal with the same amplitude, frequency and phase
(b) sinusoidal with the same frequency, but possibly different amplitude and phase
(c) non-sinusoidal
(d) sinusoidal with a different frequency

Q6. The network layer is concerned with __________ of data.
(a) packets
(b) frames
(c) bits
(d) bytes

Q7. VHF wave propagates with the help of
(a) ground
(b) ionosphere
(c) troposphere
(d) none of these.

Q8. The number of bits needed to address 4K memory is:
(a) 6
(b) 8
(c) 16
(d) 12

Q9. In binary system decimal 10.75 is represented by
(a) 10.1010
(b) 1010.11
(c) 111.1111
(d) 101.1110

Q10. Assertion(A): A periodic function satisfying Dirichlet’s condition can be expanded into a Fourier series.
Reason(R): A Fourier Series is a summation of weighted sine and cosine waves of the fundamental frequency and its harmonics.
(a) Both A and R are True and R is the correct explanation of A.
(b) Both A and R are True but R is not the correct explanation of A.
(c) A is True but R is False.
(d) A is False but R is True.

SOLUTIONS

S1. Ans. (a)
Sol. The leading power factor in an AC electric circuit is obtained by Capacitive Load. So, when a capacitor is connected in parallel with the load then capacitor produces reactive KVA into the circuit and reduces the power factor angle. Hence, power factor will be improved.

S2. Ans.(b)
Sol. Topology is the way of physical or logical arrangement of each and every node in the network with the help of links. Based on the requirement of application of the network topology are chosen. These are – Ring, Star, Bus, Mesh, Tree and hybrid topology.

S3. Ans.(d)

S4. Ans.(a)
Sol. Digital modulation is less prone to noise interference as compared to analog modulation. So, satellite communication system uses this technique.

S5. Ans.(b)

S6. Ans.(a)
Sol. In computer networks, the data which is obtained in the form of segments from transport layer is converted to packets in the network layer. These packets are then sent to data link layer where it is converted into frames.

S7. Ans (c)
Sol. VHF waves can travel long distances by tropospheric ducting due to refraction by temperature gradients in the atmosphere.

S8. Ans.(d)
Sol. 4K = 2^2 × 2^10 = 2^12 Bytes
We know that,
⇒ memory size = 2^n × m
where,
n is number of address lines
m is number of data lines
⇒ 4K memory = 2^12 × 8 bits
Hence, 12 bits are needed for address and 8 bits for data lines.

S9. Ans (b)
Sol. Converting 10.7510 in Binary system here so:
The Whole part(i.e., left side of decimal) of a number is obtained by dividing:

Binary representation of 1010 = 10102
The fractional part of number is found by multiplying on the basis new

Binary Representation of 0.7510 = 0.112
Add up both whole and fractional part, we get:
10102 + 0.112 =1010.112
Therefore, 10.7510 = 1010.112

S10. Ans.(b)
Sol. Fourier Series is –
f(t) = a_o + ∑_(n=1)^∞▒( a_ncosω_ot + b_nsinω_ot)

Quiz Electronics Engineering 29 Aug 2020

Quiz Electronics Engineering
Exam: NIC
Topic: Miscellaneous
Date: 29/08/2020

Each Question carries 1 Mark
Negative Marking: 1/4
Time: 10 Minutes

Q1. Which one of the following statements about the 8085 is TRUE?
(a) only accumulator can be loaded with an 8-bit number in a single instruction
(b) The processor can be interrupted even after it executes HLT instruction.
(c) Program and Data Memories are different.
(d) When HOLD input is activated, the processor can execute register to register instructions.

Q2. The capacitance ‘C’ is equal
(a) C=ν/q
(b) C=q/ν
(c) q=c/ν
(d) q=ν/c

Q3. The distance between maxima and minima of a standing wave is
(a) λ/4
(b) λ/2
(c) λ
(d) 2 λ

Q4. The inverse Fourier Transform of 𝛿(f) is
(a) e^(-j2πt)
(b) u(t)
(c) 𝛿(t)
(d) 1

Q5. How many bits are required to encode 32 level PCM:
(a) 6
(b) 5
(c) 4
(d) 3

Q6. The unit of conductivity is
(a) ohm/m
(b) mho/m
(c) ohm. m
(d) mho. m

Q7. Consider Fourier representation of continuous and discrete-time systems. The complex exponential(i.e. signals), which arise in such representation, have
(a) same properties always
(b) different properties always
(c) non-specific properties
(d) mostly same properties

Q8. The address bus of 8085 is a group of:
(a) 8 lines
(b) 12 lines
(c) 16 lines
(d) 32 lines

Q9. The correct relationship between KVA and cos ϕ is
(a) (√k W)/cosϕ=KVA
(b) kW/cosϕ=KVA
(c) √(kW/cosϕ)=KVA
(d) None of the above

Q10. A 1 ms pulse can be converted into a 10 ms pulsed by using which one of the following?
(a) An astable multivibrator
(b) A J-K flip-flop
(c) A bistable multivibrator
(d) A monostable multivibrator

SOLUTIONS

S1. Ans.(d)
Sol.
Along with accumulator there are other general purpose or special registers which can store 8-bit data in a single instruction.
‘HLT’ means the execution of the program is completed. So, microprocessor can’t be interrupted after it executes HLT instruction.
When HOLD signal is ‘HIGH’ then microprocessor completes the machine cycle which was running and after its completion stops the use of data and address bus.
Program and data memories are same in 8085 microprocessor. Same memory space can be used for both purpose.

S2. Ans.(b)
Sol. Capacitance of a capacitor is defined as the ratio of the charge stored on the plates to the potential difference between the plates.
⇒ C=q/V

S3. Ans.(a)
Sol. Distance between two maxima or two minima is λ/2 and the distance between maxima and minima of a standing wave is λ/4.

S4. Ans.(d)
Sol. Fourier Transform of 1 is
1 ↔┴( F.T ) 𝛿(f)
1 ↔┴( F.T ) 2π𝛿(ω)

S5. Ans.(b)
Sol. Given:
Quantization level(L) = 32
We know that Quantization Level is
L = 2n where n is number of bits
Now,
L = 2n = 32 = 25
So, n = 5.
Therefore, number of bits = 5

S6. Ans.(b)
Sol. Conductivity=1/Resistivity=1/(ohm. m)
So, unit of conductivity = mho/m.

S7. Ans.(a)

S8. Ans.(c)
Sol. Features of 8085 microprocessor is –
8-bits data bus
16-bits address bus
NMOS technology
40 pins dual-in line package
clock frequency is 3 MHz.
clock cycle is 300 ns.
74 basic instructions and 246 opcodes

S9. Ans.(b)
Sol. Power factor is
cosϕ =KW/KVA

S10. Ans.(d)
Sol. A Monostable multi-vibrator is used as pulse stretcher. It is generally used to increase the width of a pulse or to produce a time delay within a circuit. The frequency of the output signal always remain same as that of the trigger pulse input, the only difference is in the pulse width.

Quiz Electronics Engineering 25 Aug 2020

Quiz Electronics Engineering
Exam: NIC
Topic: Miscellaneous
Date: 25/08/2020

Each Question carries 1 Mark
Negative Marking: 1/4
Time: 10 Minutes

Q1. Coherent demodulation of FSK signal can be detected using
(a) matched filter
(b) bandpass filters and envelope detector
(c) correlation receiver
(d) discriminator detection

Q2. Which instruction in an 8085 processor can clear the accumulator?
(a) XRA A
(b) JNZ 2100H
(c) STA 2000H
(d) MOV B, C

Q3. Difference between a switch and Hub
(a) both are same
(b) switch avoids flooding
(c) Hub avoids broadcast
(d) None of the above

Q4. In a broadside array, the maximum radiation occurs:
(a) along the array
(b) at 45° to the array
(c) perpendicular to the array
(d) None of the these

Q5. When a function f(n) is said to be left sided?
(a) f(n) = 0 for n < 0
(b) f(n) < 0 for n > 0
(c) f(n) = ∞ for n < n_o
(d) f(n) = 0 for n > n_o

Q6. Initially the number decimal 8 is stored. If instruction RAL is executed twice, the final number stored will be:
(a) Decimals 8
(b) Decimal 32
(c) Decimal 16
(d) Decimal 2

Q7. The efficiency of an LED for generating light is directly proportional to the
(a) current injected
(b) temperature
(c) applied voltage
(d) level of doping

Q8. One byte is a group of how many bits?
(a) 2 bits
(b) 4 bits
(c) 8 bits
(d) 16 bits

Q9. The frequency of DC supply is
(a) zero
(b) 16 2/3 Hz
(c) 50 Hz
(d) 100 Hz

Q10. A discrete LTI system is non-causal if its impulse response is
(a) a^nu(n – 2)
(b) a^(n-2)u(n – 2)
(c) a^(n+2)u(n)
(d) a^nu(n + 2)

SOLUTIONS

S1. Ans.(c)
Sol. The Coherent demodulation of FSK signal can be detected using correlation receiver. It is a radio-astronomy receiver in which either the noise power from a single antenna is split and multiplied with itself or the noise power from the two arms of an are multiplied together.

S2. Ans.(a)
Sol. ‘XRA’ means Exclusive OR operation is applied between the contents of the accumulator and the contents of the operand i.e. register or memory. The result is stored in the accumulator.
Here, Ex-OR operation is applied between the contents of the accumulator only. We know that if the inputs are same then the output of the Ex-OR operation will be zero. So, the final result is ‘0’ in the accumulator i.e. accumulator data is cleared.

S3. Ans.(b)
Sol. Hub and Switch both are used for connecting large number of computers together to a network. In Hub, there is no control over flow of data but in case of switch if the flow of data is over limit then it also functions in stopping those data.
difference between Hub and Switch

S4. Ans.(c)
Sol. In a broadside array, the direction of the maximum radiation is perpendicular to the axis of array but in the end fire array, the direction of the maximum radiation is along the axis of array.

S5. Ans.(d)
Sol. If a signal is having non-zero value to the left of any fixed value of n till –∞ then signal is said to be left sided.
Here, the fixed discrete time is n_o so f(n) = 0 for n > n_o.

S6. Ans. (b)
Sol. RAL(Rotate Accumulator Left) instruction rotate the accumulator towards left along with the carry present. If instruction RAL is executed once the number gets doubled.

At first RAL executed: –

Second time RAL executed: –

Therefore, the final number stored will be 25 = 32.

S7. Ans.(a)

S8. Ans.(c)

S9. Ans.(a)
Sol. In DC supply, current or voltage does not vary with time so frequency of dc supply is zero.

S10. Ans.(d)
Sol. A discrete LTI system is causal if h(n) = 0 for n < 0.
But, here h(n) ≠ 0 for n = -2 so system is non-causal.

Quiz Electronics Engineering 24 Aug 2020

Quiz Electronics Engineering
Exam: NIC
Topic: Miscellaneous
Date: 24/08/2020

Each Question carries 1 Mark
Negative Marking: 1/4
Time: 10 Minutes

Q1. In 8086 microprocessor the following has the highest priority among all type of interrupts.
(a) DIV 0
(b) NMI
(c) Type 255
(d) Overflow

Q2. Sampling technique in communication system leads to
(a) better efficiency
(b) cheaper equipment
(c) simpler operation
(d) high speed of communication

Q3. Maxwell’s curl equation for the static electric field E can be expressed as
(a) Δ . E = 0
(b) Δ × E = constant
(c) Δ × E = 0
(d) Δ . E = constant

Q4. Assertion(A): Zero state response is usually referred as particular solution of the filter.
Reason(R): Particular solution depends on only the input but not on the initial conditions.
(a) Both A and R are True and R is the correct explanation of A.
(b) Both A and R are True but R is not the correct explanation of A.
(c) A is True but R is False.
(d) A is False but R is True.

Q5. Filament lamp makes use of
(a) Chemical effect
(b) Heating effect
(c) Magnetic effect
(d) None of these

Q6. The Boolean equation X ={(A+B ̅ )(B+C)}B can be simplified to
(a) X = A ̅B
(b) X=AB ̅
(c) X=AB
(d) X = A ̅B ̅

Q7. A microcontroller differs from a microprocessor in terms of:
(a) I/O interfaces and Instruction decoding
(b) Memory configuration and I/O interfaces
(c) Data bus width and clock speed
(d) Memory configuration and Instruction decoding

Q8. Which of the following pulse modulating systems is analog?
(a) PWM
(b) PCM
(c) both (a) and (b) above
(d) none of the above

Q9. Transient response analysis is done for_________ systems.
(a) Unstable
(b) Stable
(c) Conditionally stable
(d) Marginally stable

Q10. The magnetic field strength(H) for infinite straight line is given by
(a) H = 2πr/I
(b) H = 4πr/I
(c) H = I/2πr
(d) H = I/4πr

SOLUTIONS

S1. Ans.(b)
Sol. Based on priority the interrupts are arranged in descending order as follows: –
⇒ NMI > Software Interrupt > Internal Interrupt > Reset

S2. Ans.(d)

S3. Ans.(c)
Sol. Maxwell’s curl equation for the static electric field E is
Δ × E=0

S4. Ans.(a)

S5. Ans.(b)
Sol. Filament lamp normally use heating effect to glow. It provides hindrance to the flow of current as a result of which it releases energy in the form of heat.

S6. Ans.(c)
Sol. X = [(A+B ̅ )(B+C)]B
=[AB+AC+BB ̅+B ̅C]B [█(∵ B B ̅=0@∵ BB=B)]
= AB + ABC + 0 + 0
=AB(1+C) [∵ 1+C=1]
=AB

S7. Ans.(b)
Sol. In Microcontroller, the memory and peripheral devices are connected externally but in microprocessor, the memory and the peripheral devices are present inside it.

S8. Ans.(a)
Sol. Pulse Width Modulation (PWM) is a powerful technique for controlling analog circuits with a microprocessor’s digital outputs.

S9. Ans (b)
Sol. Transient response analysis is done only when system is stable. If system unstable then no need to proceed further for analysis.

S10. Ans.(c)

Quiz Electronics Engineering 20 Aug 2020

Quiz Electronics Engineering
Exam: NIC
Topic: Miscellaneous
Date: 20/08/2020

Each Question carries 1 Mark
Negative Marking: 1/4
Time: 10 Minutes

Q1. Which of the following analog modulation scheme requires the minimum transmitted power and minimum channel band-width?
(a) SSB
(b) DSB-SC
(c) VSB
(d) AM

Q2. A microprocessor is called an ‘n-bit microprocessor’ depending on –
(a) register length
(b) size of internal data bus
(c) size of external data bus
(d) None of these

Q3. Two charge are placed at a small distance apart. If a glass slab is placed between them, the force between the charges will
(a) not change
(b) increase
(c) decrease
(d) reduces to zero.

Q4. Assertion(A): The stability of the system is assured if the Region of Convergence(ROC) includes the unit circle in the z-plane.
Reason(R): For a causal stable system all the poles should be outside the unit circle in the z-plane.
(a) Both A and R are True and R is the correct explanation of A.
(b) Both A and R are True but R is not the correct explanation of A.
(c) A is True but R is False.
(d) A is False but R is True.

Q5. If x and y are Boolean variables, which one of the following is the equivalent of x ⊕ y ⊕ xy.
(a) x + y ̅
(b) x + y
(c) 0
(d) 1

Q6. If a parallel resonant circuit is shunted by a resistance then
(a) circuit impedance is decreased
(b) the gain of the circuit is increased
(c) ‘Q’ of the circuit is increased
(d) None of these

Q7. The final value theorem is
(a) lim┬(k →∞ )⁡〖x(k)〗 = lim┬(z →0 )⁡〖(〖z-1)〗^(-1) 〗 X^+(z^(-1))
(b) lim┬(k →∞ )⁡〖x(k)〗 = lim┬(z →1 )⁡〖X^+ 〗(z)
(c) lim┬(k →∞ )⁡〖x(k)〗 = lim┬(z →0 )⁡〖(z^(-1))〗 X^+(z)
(d) lim┬(k →∞ )⁡〖x(k)〗 = lim┬(z →1 )⁡〖(z-1)〗 X^+(z)

Q8. Match List-I with List-II and select the correct answer using codes given below the lists:
List-I
A. At peak point
B. At Valley point
C. Reverse bias region
D. Beyond valley point
List-II
1. Low tunnelling current
2. Zero tunnelling current
3. High diffusion current
4. High tunnelling current
Codes:
A B C D
(a) 3 2 4 1
(b) 1 2 4 3
(c) 3 4 2 1
(d) 1 4 2 3

Q9. Compact disk is which type of memory?
(a) Primary Memory
(b) RAM
(c) ROM
(d) Secondary Memory

Q10. An electric charge of Q coulombs is located at the origin. Consider electric potential V and electric field intensity E at any point (x, y, z). Then
(a) E is a vector and V is a scalar.
(b) E and V both are vectors.
(c) E is a scalar and V is a vector.
(d) E and V both are scalars.

SOLUTIONS

S1. Ans.(a)
Sol. The bandwidth of SSB signal is minimum as compared to all other modulation scheme mentioned above. So, Channel bandwidth is minimum. It also requires minimum transmitted power.

S2. Ans.(b)
Sol. ‘n-bit microprocessor’ means microprocessor consists of n-bit internal data bus. So, it depends upon the size of internal data bus.

S3. Ans.(c)
Sol. From Coulomb’s law, we get
F = (Q_1 Q_2)/(4πε_0 ε_r r^2 )
For glass slab, ε_r > 1
As denominator increases, so final value decreases.
Hence, the force between the charges will decrease between two charges.

S4. Ans.(c)
Sol. For a causal system all the poles should lie inside the unit circle in z-plane.

S5. Ans.(b)
Sol.
f=x ⊕(y ⊕xy)
=x ⊕[y.(xy) ̅+xy.y ̅ ]
= x ⊕[y.(x ̅+y ̅)+xy.y ̅ ] [ (xy) ̅ = x ̅+y ̅ & y.y ̅ = 0]
=x ⊕[y (x ̅+y ̅ )]
=x ⊕[y x ̅ + yy ̅]
=x ⊕y x ̅
=xy ̅+x+yx ̅
= x(y ̅ + 1) + yx ̅
= x + yx ̅ = (x + x ̅)(x + y) [By boolean algebra property]
= x + y
Therefore, the equivalent of x ⊕ y ⊕ xy is (x + y).

S6. Ans.(a)
Sol. Net impedance,
Z = √(R ² +X² )
where,
R = resistance of circuit
X = reactance of circuit
When parallel resonant circuit is shunted by a resistance then reactance of the circuit decreases hence circuit impedance is decreased.

S7. Ans.(d)

S8. Ans.(b)

S9. Ans.(d)
Sol.
Primary Memory consists of Cache, RAM, Registers.
Secondary Memory consists of CD, DVD, Hard Disk, Pen Drive, Magnetic Tapes etc.

S10. Ans.(a)
Sol. Electric potential is a scalar quantity always and Electric Field is a vector quantity always.