NPCIL Placement Paper

                                       NPCIL Placement Paper - Electronics 

1. Power diode is generally made from
a) Silicon
b) Germanium
c) Both
d) None of these

2. When the both junction of NPN diode is reverse biased, then the diode is in which mode
a) Active
b) Cutoff
c) Saturation
d) inverted

3. Which transistor mode gives the inverted output
a) Common Emitter
b) Common Base
c) Common Collector
d) None of these

4. Which coupling gives the higher gain in case of amplifier
a) Capacitor coupling
b) Impedance coupling
c) Transformercoupling

5. Which distortion is least objectionable in audio amplification
a) Phase
b) Frequency
c) Harmonic
d) Intermediation

6. A narrow band amplifier has a band pass nearly…………of central frequency
a) 33.3%
b) 10%
c) 50%

7. Phase shift oscillator consists
a) RL
b) RC
c) RLC

8. Multivibrater Produces
a) Sine wave
b) Square wave
c) Smooth wave
d) sawtooth

9. Convert the 101101 Binary number into octal no
a) 65
b) 55
c) 51
d) 45
Ans: 55

10. 10 in BCD
a) 10100
b) 1100
c) 010111
d) None of these
Ans: None of these

11. Which PNP device has a terminal for synchronizing purpose
a) SCS
b) Triac
c) Diac
d) SUS

12. output resistance of ideal OP AMP is
a) 0
b) 1
c) infinite
d) very high
ANS: 0

13. Free electron exists in which band
a) 1
b) 2
c) 3
d) Conduction band

14. Ripple factor of half wave rectifier
a) 1.21
b) 0.48
c) 0.5

15. Transistor that can be used in enhancement mode
a) NPN
b) UJT
c) JFET
d) MOSFET

16. Following contributes to harmonic distortion in Amplifier
a) +Ve feedback
b) –Ve feedback
c) Defective active device

17. High cutoff frequency
a) CB
b) CC
c) CE

18. Which is used as data selector?
a) Encoder
b) Decoder
c) modulator
d) Demodulator

19. Read write capable memory
a) RAM
b) ROM
c) Both
d) None of these

20.the radix or base of hexadecimal number system is ———–
a) 8
b) 16
c) 5
d) none of these
Ans: 16

21.the no of 1’s in the binary representation of the expression 162*9+162*7+16*5+3 are
a) 10
b) 23
c) 6
d) 4

22. the no of latches in F/F are ——-
a) 1
b) 2
c) 3
d) 4

23.how many flip-flops are required to construct Mod -12 counter
a) 5
b) 4
c) 12
d) none
Ans: 4

24. which logic gate has the output is compliment of its input ———-
a) OR
b) AND
c) NOT
d) X-OR
Ans: NOT

25.no.of 2-input multiplexers needed to construct a 210 input multiplexer…….
a) 12
b) 31
c) 20
d) 16

26.By adding inverters to the inputs and output of a AND gate we can obtain ……………
a) OR
b) AND
c) NOT
d) X-OR
Ans: X-OR

27.how many NAND gates are needed to realize OR gate ————–
a) 1
b) 2
c) 3
d) 4
Ans: 3

28.which is the first integrated logic family —————
a) RTL
b) DTL
c) TTL
d) none of these

29. Which logic gate has output high if and only if all inputs are low ———?
a) NOR
b) NAND
c) X-NOR
d) AND
Ans: NAND

30.According to Boolean algebra 1+A+B+C =
a) A
b) A+B+C
c) 1
d) none of these
Ans: 1

31. If a=0x6db7 and b=0x2ae9 then what is the value of a”b————–
a) binary number for 1001.1101?
b) decimal number for 19?
c) excess-3 code for 29?

32.what is the value of A’+1 ?
a) A
b) A’
c) 1
d) none of these
Ans: 1

33.2 in 4 bit number one bit indicates sign of the number then the locations are from
a) -8 to 8
b) -7 to 7
c) -16 to 16
d) None

34.Which of the following are correct?
1)A flip-flop is used to store 1-bit of information
2)Race around condition occurs in JK flip flop when both the inputs are 1
3)Master slave flip flop is used to store 2 bits of information
4)A transparent latch consists of a D- flip flop
a) 1,2,3
b) 1,3,4
c) 1,2,4
d) 2,3,4
Ans: 1,2,4

35.some non zero DC voltage is to RC low pass circuit then the DC voltage in the output contains
a) Same as in input
b) Higher than input
c) Zero
d) Slightly increases

36.if the output of the gate is always high then the gates applied to this logic are 0,0
a) NAND and EX-NOR
b) NAND and NOR
c) AND and X-NOR
d) OR and XOR
Ans:a

37.Thermal Run away is not possible in FET bcz the flow of
a)minority careers
b)Transconductance
c)_____
d)none
Ans : minority careers

38.which of the following is/are true about 1’s and 2’s compements:
i)In 1’s complement form. 0 has two representations
ii)in 1’s complement, the magnitude of lowest number is equal to the magnitude of highest number
iii)In 2’s complement, 0 has two representations
a) i only
b) i and ii
c) iii only
d) all of these

39.In the hybrid parameter model of a transistor reverse transfer voltage ratio and forward transfer current ratio are respectively given by:
a) h11 and h21
b) h12 and h11
c) h21 and h11
d) None of these

40.The largest negative no can be represented with 8 bits in 2’s compliment representation?
a)-256
b)-255
c)-127
d)-128
Ans: -128

41. How many NAND gates required to implement AB+CD+EF
a) 1
b) 2
c) 3
d) 4
Ans: 4

42. Transparent latch is seen in which type of flip flop
a) SR FF
b) D FF
c) JK FF
d) D FF
Ans: D FF

43. Odd parity generator uses which logic?
a) Digital
b) Analog
c) Sequential
d) none

44. Which type of ADC is fastest?
a) SARC
b) Counter type
c) Intigrated type
d) Flash
ANS: Flash/Parallel

45. Which one of the following is fastest read/writable memory?
a) PROM
b) EEPROM
c) Flash
d) none
Ans: Flash

46. In array programming which one is used
a) SISD
b) PISD
c) MISD
d) None

47.Which one of the following has high I/p impedance
a) CC
b) CB
c) CE
d) None

48. The maximum time allowed time for each flip flop for a mod 10 synchronous counter if each flip flop delay is 25ns.
a) 25 ns
b) 50 ns
c) 100 ns
d) none

49. The resolution for a DAC is given by 0.4% then no. of bits of DAC is
a) 8- bits
b) 16- bits
c) 32- bits
d) none
Ans: 8- bits

50. The chip capacity is 256 bits, then the no.of chips required to build 1024 B memory Is
a) 32
b) 16
c) 15
d) 4