Quiz Electronics Engineering 29 Sep 2020

Quiz Electronics Engineering
Exam: NIC
Topic: Miscellaneous
Date: 29/09/2020

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

Q1. Which of the following statements about electric field lines associated with electric charge is false?
(a) Electric field lines can be either straight or curved.
(b) Electric field lines form closed loops.
(c) Electric field lines begin on positive charges and end on negative charges.
(d) Electric field lines do not intersect.

Q2. For a message signal m(t) = cos(2πfmt) and carrier of frequency fc, which of the following represents a SSB signal?
(a) cos(2πfmt) cos(2πfct)
(b) cos(2πfct)
(c) [1 + cos(2πfmt) cos(2πfct)]
(d) cos[2π(fc + fm)t]

Q3. Electronic mail uses which Application layer protocol?
(a) SMTP
(b) HTTP
(c) FTP
(d) SIP

Q4. A circuit component that opposes the change in circuit voltage is
(a) Resistance
(b) Inductance
(c) Capacitance
(d) All the above

Q5. The abbreviation TTL stands for
(a) Transistor-transformer logic
(b) Transistor-transistor logic
(c) Transmitter transistor load
(d) Tuned transistor loop

Q6. 8085 has ___ software restarts and ___ hardware restarts.
(a) 10, 5
(b) 6, 6
(c) 7, 5
(d) 8, 4

Q7. A transistor is said to be in quiescent state when
(a) no signal is applied to the input
(b) no currents are flowing
(c) it is unbiased
(d) emitter junction and collector-junction biases are equal

Q8. The Fourier transform of u(t) is
(a) 1/jω
(b) jω
(c) π𝛿(ω) + 1/jω
(d) 1/(1+jω)

Q9. Which of the following expressions is true for apparent power in an A.C. circuit?
(a) VI cos ∅
(b) V_(r.m.s.) ×I_(r.m.s.)
(c) V_av.×I_av.
(d) V_peak×I_peak

Q10. For electromagnetic wave propagation in free space , the free space is defined as
(a) σ = 0, ε = 1, µ ≠ 1, p ⃗ ≠ 0, j ⃗ = 0
(b) σ = 0, ε = 1, µ = 1, p ⃗ = 0, j ⃗ = 0
(c) σ ≠ 0, ε > 1, µ < 1, p ⃗ ≠ 0, j ⃗ = 0
(d) σ = 0, ε = 1, µ = 1, p ⃗ ≠ 0, j ⃗ ≠ 0

SOLUTIONS

S1. Ans.(b)
Sol. Electric Field lines never form closed loop. Either they converge at the negative charge or direct towards infinity.

S2. Ans.(d)
Sol. In case of SSB-SC signal, either there is USB or LSB. Both cannot be present simultaneously.
Here, cos[2π(fc + fm)t] represents the Upper Side Band of either AM or SSB-SC signal.

S3. Ans.(a)
Sol. Email uses various protocols like SMTP, IMAP and POP. The most prominent one used in application layer is Simple Mail Transfer Protocol (SMTP).

S4. Ans.(c)

S5. Ans.(b)
Sol. TTL stands for Transistor-Transistor Logic. TTL is a logic family built from Bipolar Junction Transistors. TTL circuit design offered higher speed or lower power dissipation to allow design optimization. It employs a transistor with multiple emitters having more than one input.

S6. Ans.(d)
Sol. Software and Hardware Interrupts restart the operation in the 8085 microprocessor. There are 4 Hardware interrupt(TRAP, RST 5.5, RST 6.5, RST 7.5) and 8 Software Interrupts(RST_0 to RST_7). Hence, there are 4 hardware restarts and 8 software restarts.

S7. Ans.(a)
Sol. Quiescent state means “at rest”. At this state power supply is ON and stable and defined by the voltage and current present in the circuit. It shows the zero signal state of the transistors. This state describes the behavior of the transistor. The quiescent point in transistor is related to direct biasing of current to base.

S8. Ans.(c)

S9. Ans (b)
Sol. In an AC circuit, the product of the r.m.s voltage and the r.m.s current is called Apparent Power.

S10. Ans.(d)
Sol. In free space,
σ = 0,
ε = 1,
µ = 1,
Poynting vector, p ⃗ ≠ 0,
Current Density, j ⃗ ≠ 0

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