1. In intrinsic semiconductor
(A) The electron density is twice the whole density
(B) The electron density is thrice the whole density
(C) The electron density is square root of the whole density
(D) The electron density is same as the whole density
Answer: (D)
2. PN junction diode can be used as a/an
(A) Oscillator
(B) Amplifier
(C) Insulator
(D) Rectifier
Answer: (D)
3. Norton’s equivalent form in any complex impedance circuit consists of
(A) An equivalent current source in parallel with an equivalent resistance.
(B) An equivalent voltage source in series with an equivalent resistance.
(C) An equivalent current source in parallel with equivalent impedance.
(D) An equivalent voltage source in series with equivalent impedance.
Answer: (C)
4. Zener diode is a
(A) Reverse biased diode
(B) Variable voltage source
(C) Constant current source
(D) Forward biased diode
Answer: (A)
5. Which of the following oscillator make use of both positive and negative feedbacks?
(A) Hartley oscillator
(B) Colpit’s oscillator
(C) Phase shift oscillator
(D) Wein-Bridge oscillator
Answer: (D)
6. Superposition theorem can be applied only to circuits having
(A) Resistive elements
(B) Passive elements
(C) no-linear elements
(D) Linear bilateral elements
Answer: (D)
7. Identify the fastest analogue to digital converter
(A) Ramp conversion
(B) Parallel conversion
(C) Successive approximation
(D) Dual-slope integration
Answer: (B)
8. 1 K memory device contain
(A) 1064 memory cells
(B) 1024 memory cells
(C) 512 memory cells
(D) 640 memory cells
Answer: (B)
9. Which logic function has the output low only when both inputs are high?
(A) NOR
(B) OR
(C) AND
(D) NAND
Answer: (D)
10. In FM, when frequency deviation doubled, then
(A) Modulation Index is decreased
(B) Modulation Index is doubled
(C) Modulation Index halved
(D) No change occurs in modulation index values
Answer: (B)
11. Out of the following memory types, one that is volatile is
(A) Magnetic disc
(B) Ferrite core
(C) Semiconductor ROM
(D) Semiconductor RAM
Answer: (D)
12. An SCR can be formed by using
(A) 2 npn transistors
(B) 2 pnp transistors
(C) 1 npn and 1 pnp transistor
(D) 2 pn diode
Answer: (C)
13. The pH of human blood is between
(A) 6.5 to 7
(B) 7.5 to 8
(C) 8 to 9
(D) 4.5 to 5
Answer: (B)
14. What is SIM?
(A) Select Interrupt Mask
(B) Sorting Interrupt Mask
(C) Set Interrupt Mask
(D) Start Instruction Mode
Answer: (C)
15. Quantization noise occurs in
(A) TDM
(B) PCM
(C) FDM
(D) WDM
Answer: (B)
16. Which antenna gets circularly polarized?
(A) Yagi-Uda
(B) Dipole
(C) Parabolic
(D) Helical
Answer: (D)
17. VSWR (Voltage Standing Wave Ratio) is always
(A) More than 1
(B) Less than 1
(C) 1
(D) 0.4
Answer: (A)
18. The ladder network used in D/A converter is
(A) Weighted resistance ladder
(B) R – R ladder
(C) R – 2R ladder
(D) R – C ladder
Answer: (C)
19. Latch is a
(A) T flip-flop
(B) Master-slave JK flip-flop
(C) D flip-flop
(D) JK flip-flop
Answer: (C)
20. In LED, light is emitted, because
(A) Diode emits light when gets heated.
(B) Recombination of charge carrier takes place.
(C) Light is made to reflect due to lens action.
(D) LED amplifies the light falling on it.
Answer: (B)
Directions (Q. Nos. 21 to 30): The following items consist of two statements, one labelled the “Assertion (A)” and the other labelled the “Reason (R)”. You are to examine these two statements carefully and decide if the “Assertion A” and the “Reason (R)” are individually true and if so, whether the Reason is a correct explanation of the Assertion. Select your answers to these items using the codes given below and mark your answer accordingly.
Codes:
(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 correct explanationof (A).
(C) (A) is true, but (R) is false.
(D) (A) is false, but (R) is true.
21. Assertion (A): 8421 code is weighted code.
Reason (R): 8421 code is self-complementary.
Answer: (C)
22. Assertion (A): A stack is a type of non-sequential access memory system.
Reason (R): Memory stacks help in keeping track of return addresses and saving data for subroutines.
Answer: (D)
23. Assertion (A): TEM waves exist in a waveguide.
Reason (R): Phase velocity and wave impedance for TEM waves are independent of the frequency of the waves.
Answer: (D)
24. Assertion (A): In FSK, a binary 1 usually produces a higher carrier frequency than a binary 0.
Reason (R): FSK maintains a constant amplitude carrier.
Answer: (B)
25. Assertion (A): An LTI discrete system represented by the difference equation y(n + 2) – 5y (n + 1) + 6y(n) = x(n) is unstable.
Reason (R): A system is unstable if the roots of the characteristic equation lie outside the unit circle.
Answer: (A)
26. Assertion (A): Stimulated emission is the key to the operation of LASER.
Reason (R): An important property of LASER radiation is its coherence, under which is meant the correlation between the phases of oscillation at different positions in space and at various moments of time.
Answer: (A)
27. Assertion (A): R-2R ladder type D/A converter has a higher speed of conversion than a weighted resistance D/A converter.
Reason (R): R–2R ladder type converter uses a smaller number of components than the weighted resistance D/A converter.
Answer: (C)
28. Assertion (A): UJT is used in relaxation oscillators.
Reason (R): UJT has negative resistance region in its characteristics.
Answer: (A)
29. Assertion (A): The race hazard problem does not occur in combinational circuits.
Reason (R): The output of a combinational circuit depends upon present inputs only.
Answer: (A)
30. Assertion (A): Digital communication needs some synchronisation signals.
Reason (R): ‘bit syn’ signal isrequired in time divisionmultiplexing to distinguishgroups of data.
Answer: (B)
31. Consider the following logic families:
1. MOS
2. TTL
3. RTL
4. ECL
The correct sequence of the logic families in the order of their increasing noise margin is
(A) 3, 4, 1, 2
(B) 3, 4, 2, 1
(C) 4, 3, 2, 1
(D) 4, 3, 1, 2
Answer: (B)
32. Which is the correct sequence in the generation of PCM?
1. Sampling
2. Converting to PAM
3. Quantization
4. Adding of supervisory signal
5. Encoding
(A) 1, 2, 5, 3, 4
(B) 1, 5, 2, 3, 4
(C) 1, 2, 3, 5, 4
(D) 4, 5, 1, 2, 3
Answer: (C)
33. Consider the following logic families:
1. MOS
2. CMOS
3. DTL
4. TTL
The correct sequence of power dissipation in increasing order is given by
(A) 2, 1, 3, 4
(B) 2, 1, 4, 3
(C) 1, 2, 3, 4
(D) 1, 2, 4, 3
Answer: (A)
34. The data can be transmitted by following means:
1. Coaxial cables
2. MMF
3. SMF
4. Twisted wire cable
The correct sequence in the increasing order of Bandwidth is
(A) 2, 3, 1, 4
(B) 4, 1, 2, 3
(C) 4, 1, 3, 2
(D) 1, 4, 2, 3
Answer: (B)
35. Consider the following devices:
1. BJT in CB mode
2. BJT in CE mode
3. JFET
4. MOSFET
The correct sequence of these devices in increasing order of their impedance is
(A) 2, 1, 3, 4
(B) 2, 1, 4, 3
(C) 1, 2, 3, 4
(D) 1, 2, 4, 3
Answer: (C)
Match the following (Q. Nos. 36 – 45):
36. List – I List – II
a. SCR i. dc drive control
b. Triac ii. Induction motor control
c. Chopper iii. Unidirectional
d. Cycloconverter iv. Bidirectional
Codes:
a b c d
(A) iv iii i ii
(B) i ii iii iv
(C) iii iv i ii
(D) i iv ii iii
Answer: (C)
Answer: (A)
38. List – I List – II
a. Varistor i. nonlinear resistance
b. Varactor diode ii. Nonlinear reactance
c. Gunn diode iii. Negative resistance
d. PIN diode iv. Controllable impedance type
Codes:
a b c d
(A) i ii iii iv
(B) ii iii iv i
(C) iii iv i ii
(D) iv i ii iii
Answer: (A)
39. List – I List – II
a. Klystron i. Cross-field device
b. Reflex Klystron ii. Bunching
c. Magnetron iii. Velocity modulation
d. Gunn diode iv. Negative resistance
Codes:
a b c d
(A) ii iii i iv
(B) i ii iii iv
(C) iv i ii iii
(D) i ii iv iii
Answer: (A)
40. List – I List – II
a. LED i. Stimulated emission
b. LASER ii. Spontaneous emission
c. Solar Cell iii. Power generator
d. Photo diode iv. Detector
Codes:
a b c d
(A) i ii iii iv
(B) ii i iii iv
(C) iii iv i ii
(D) iv i ii iii
Answer: (B)
41. List – I List – II
a. DAA i. Program control instruction
b. LXI ii. Data movement instruction
c. RST iii. Interrupt instruction
d. JMP iv. Arithmetic instruction
Codes:
a b c d
(A) i ii iii iv
(B) iv ii iii i
(C) iii iv i ii
(D) ii i iii iv
Answer: (B)
42. List – I List – II
a. 8031 i. Multiplexer
b. 7490 ii. Demultiplexer
c. 74155 iii. Microcontroller
d. 74151 iv. Decade counter
Codes:
a b c d
(A) iii iv ii i
(B) i ii iii iv
(C) ii iii iv i
(D) iii i ii iv
Answer: (A)
43. List – I List – II
a. Bourdon tube i. Distance
b. Strain gauge ii. Temperature
c. Thermistor iii. Pressure
d. LVDT iv. Stress
Codes:
a b c d
(A) i ii iii iv
(B) iii iv ii i
(C) ii iii iv i
(D) i iii ii iv
Answer: (B)
44. List – I List – II
(Types of ADC) (Characteristics)
a. Parallel comparator (i.e. flash) type i. integrating type
b. Successive approximation ii. Fastest converter
c. Dual slope iii. Conversion time is independent of the amplitude of the analogue signal
d. Counter type iv. Uses DAC in feedback path
Codes:
a b c d
(A) ii iii i iv
(B) i ii iv iii
(C) iv iii ii i
(D) iv ii iii i
Answer: (A)
45. List – I List – II
a. Flip-Flop can be used as latch i. D Flip-flop
b. Flip-Flop can be used as delayed ii. Master- Slave
c. Flip-Flop does not have race problem iii. JK
d. Flip-flop can be used as shift registers iv. R-S
Codes:
a b c d
(A) iv i ii iii
(B) ii iv i iii
(C) i iii ii iv
(D) iii i iv ii
Answer: (A)
Read the paragraph and answer the questions 46 to 50:
Microwave tubes are used as microwave amplifiers and oscillators. Three general type of microwaves tubes in which third type of tubes are useful. In this tube there is an interaction between an electron and an RF field is continuous. The Travelling Wave Tube (TWT) is the prime example of this interaction. It is an amplifier whose oscillator counterpart is called Backward Wave Oscillator (BWO). Another group of tube in which a magnetic field ensures a constant electron beam – RF field interaction and this is complimented by the cross-field amplifier (CFA). Multi-cavity Klystron is used as an amplifier of microwaves and it consists of buncher cavity and cache cavity. The Reflex Klystron is a low power and low efficiency microwave oscillator. Reflex Klystron oscillator has been replaced by various semiconductor oscillators.
46. One of the following is unlikely to be used as pulsed device. It is the
(A) Multi-cavity Klystron
(B) BWO
(C) CFA
(D) TWT
Answer: (B)
47. One of the reason why vacuum tubes eventually fail at microwave frequencies is that their
(A) Noise figure increases
(B) Transit-time becomes too short
(C) Shunt capacitive reactance becomes too large
(D) Series inductive reactance become too small
Answer: (A)
48. The Multi-cavity Klystron
(A) Has a high repeller voltage to ensure a rapid transit time.
(B) Is not a good low-level amplifier because of noise.
(C) Is not suitable for pulsed operation.
(D) Needs a long transit time through the buncher cavity to ensure current modulation.
Answer: (B)
49. Indicate the false statement. Klystron amplifiers may use intermediate cavities to
(A) Increase the band width of the device
(B) Improve the power gain
(C) Increase the efficiency of the Klystron
(D) Prevent the oscillations that occur in two cavities Klystron
Answer: (D)
50. TWT is sometimes preferred to the multi-cavity Klystron amplifier because the former
(A) Is more efficient
(B) Has a greater band width
(C) Has a higher number of modes
(D) Produces a higher output power
Answer: (B)