Quiz Electronics Engineering 31 Oct 2020

Quiz Electronics Engineering
Exam: NIC
Topic: Miscellaneous
Date: 31/10/2020

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

Q1. Which amplifier will be preferred for highest gain?
(a) Darlington pair
(b) Cascade amplifier
(c) Cascode amplifier
(d) Depends on the circuitry

Q2. Identify the correct condition for a semiconductor to be electrically neutral.
(a) N_D – p = N_A + n
(b) N_D + p = N_A + n
(c) N_D + p = N_A – n
(d) N_D – p = N_A – n

Q3. Two rectangular waveform of duration T_1 and T_2 seconds are convolved. What is the shape of the resulting waveform?
(a) Triangular
(b) Rectangular
(c) Trapezoidal
(d) semi-circle

Q4. A phase-locked loop (PLL) is a feedback circuit consisting of a:
(a) Phase detector
(b) Low-pass filter
(c) VCO
(d) All of these

Q5. How many bits are used in data bus of 8085?
(a) 7
(b) 8
(c) 9
(d) 16

Q6. If a fair coin is tossed four times. What is the probability that two heads and two tails will result?
(a) 3/8
(b) 1/2
(c) 5/8
(d) 3/4

Q7. Match List-I with List-II and select the correct answer using codes given below the lists:
List-I List-II
A. MMF 1. Conductivity
B. Magnetic Flux 2. Electric Current
C. Reluctance 3. EMF
D. Permeability 4. Resistance
Codes:
A B C D
(a) 3 4 2 1
(b) 1 2 4 3
(c) 3 2 4 1
(d) 1 4 2 3

Q8. In a certain 2-input logic gate, when A = 0, B = 0 and output C = 1, it must be …
(a) OR gate
(b) XOR gate
(c) AND gate
(d) NAND gate

Q9. Three resistance of 5 Ω each are connected in star. Values of equivalent delta resistances are
(a) 15 Ω each
(b) 2.5 Ω each
(c) 5/3 Ω each
(d) 1.5 Ω each

Q10. In OSI network architecture, the dialogue control and token management are responsibility of:
(a) data link layer
(b) Session layer
(c) transport layer
(d) network layer

SOLUTIONS

S1. Ans.(c)
Sol. A Cascode Amplifier consists of a Common Emitter stage loaded by the emitter of a Common Base stage. It has larger bandwidth because Miller effect is negligible. Its advantages are: –
larger bandwidth
high gain
moderately high input impedance
high output impedance

S2. Ans (b)
Sol. According to Law of Electrical Neutrality:
⇒ N_D + p = N_A + n
where,
N_A is acceptor concentration
N_D is donor concentration

S3. Ans.(a)
Sol. If two rectangular waveform have different duration then after convolution the shape of resulting waveform is Trapezoidal but if two rectangular waveform have same duration then after convolution the shape of resulting waveform is triangular.

S4. Ans.(d)
Sol. When PLL is used as FM demodulator, multiplier is replaced by phase detector.

S5. Ans.(b)

S6. Ans.(a)
Sol. Given:
p=P(H)=1/2
Applying the formula for binomial distribution, we get
P(X=2)= (_ ^4)C_2 (1/2)² (1-1/2)^(4-2)
⇒ P(X = 2) = (_ ^4)C_2 (1/2)^2 (1/2)² (_ ^4)C_2 /2^4
So, P(X = 2) = 6/16=3/8

S7. Ans.(c)

S8. Ans (d)
Sol. Truth Table of NAND gate: –

S9. Ans.(a)
Sol. If value of all three resistance in star circuit is same then during Star-Delta transformation the respective resistance increases by 3 times.

So, The equivalent delta resistance = 15Ω each.

S10. Ans.(b)
Sol. Session layer is responsible for setting up, controlling & then tearing down session between two computers. It helps in managing flow of data communication during a connection between two computers. The function of this layer are dialogue control, token management and synchronization.

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