## NIELIT Technical Assistant_2016_march

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Question 1 |

The thermionic emission current is given by

maxwell’s equation | |

Fermi-Dirac distribution | |

Langmuir child law | |

Richardson Dushman equation |

Question 2 |

Zener breakdown occurs

due to rupture of covalent bonds | |

due to thermally generated minority carriers | |

in lightly doped junctions | |

only in germanium diodes |

Question 3 |

Negative feedback in an amplifier

increase noise | |

reduce bandwidth | |

reduce gain | |

increase distortion |

Question 4 |

The gain of a bipolar transistor drops at high frequencies because of

early effect | |

parasitic inductive elements | |

high current in base | |

transistor capacitance |

Question 5 |

The main application of enhancement mode MOSFET is in

oscillator circuits | |

amplifier circuits | |

clipper circuit | |

switching circuits |

Question 6 |

Transducer is a device which

amplifies a given electrical signal | |

transfer an electrical signal from one place to another | |

translates a physical parameter into suitable electrical quantity | |

changes the waveform of an electrical signal |

Question 7 |

The turn ratio of a transformer is 20:1. If a load of 40 ohm is connected across the secondary. What will be the effective resistance seen looking into the primary ?

800 ohm | |

4 k ohm | |

8 k ohm | |

16 k ohm |

Question 8 |

N-channel FETs are considered better than p-channel FETs because

they consume less power | |

they have high switching time | |

mobility of electrons is greater than that of holes | |

they consume less power |

Question 9 |

In a 4-bit weighted resistor D/A converter, resistor value corresponding to LSB is 16 k ohm. The resistor value corresponding to MSB is

32 k ohm | |

15 k ohm | |

64 k ohm | |

2 k ohm |

Question 10 |

In a digital circuit, the clock is a

Flip-clop | |

Inverter | |

Monostable multivibrator | |

Free running multivibrator |

Question 11 |

In which of the following codes the successive numbers differ in only one bit position ?

ASCII | |

Gray Code | |

Excess-3 Code | |

BCD |

Question 12 |

An instruction used to set the carry flag in a computer can be classified as

data transfer | |

arithmetic | |

logical | |

program control |

Question 13 |

In FM modulation pre-emphasis is done for

low frequency components | |

high frequency components | |

middle frequency components | |

all frequency components |

Question 14 |

When modulation index of AM wave is increased from 0.5 to 1, the transmitted power

increases by 25% | |

increases by 33.3% | |

increases by 50% | |

remains same |

Question 15 |

The electric flux and field intensity inside a conducting sphere is

Minimum | |

Maximum | |

Uniform | |

Zero |

Question 16 |

A waveguide behaves as

high pass filter | |

low pass filter | |

band pass filter | |

all pass filter |

Question 17 |

In a lossless RLC circuit the transient current is

sinusoidal | |

square wave | |

triangular wave | |

non-oscillating |

Question 18 |

In an ac circuit, the maximum and minimum values of power factor can be

10 and 1 | |

1 and -1 | |

1 and 0 | |

Any positive value |

Question 19 |

In a circuit containing a complex impedance, maximum power transfer takes place when load is

pure resistance | |

equal to complex impedance | |

conjugate complex of the circuit impedance | |

inductive |

Question 20 |

The effect of doping intrinsic semiconductor is to

Move the Fermi level away from the centre of forbidden band | |

Move the Fermi level towards the centre of forbidden band | |

Change the crystal structure of the semiconductor | |

To keep the Fermi level at the middle of the forbidden band |

Question 21 |

Field Effect Transistor has

Large input impedance | |

Large output impedance | |

Large power gain | |

Small voltage gain |

Question 23 |

In an RC coupled amplifier, the voltage gain

Remains almost constant over a range of frequencies | |

Always increases with frequency | |

Always decreases with frequency | |

Is independent of frequency |

Question 24 |

Which of the following will not decrease as a result of introduction of negative feedback

Instability | |

Bandwidth | |

Overall gain | |

Distortion |

Question 25 |

To generate a 1 MHz signal, the most suitable oscillator is

Colpitt’s oscillator | |

Phase shift oscillator | |

Wien bridge oscillator | |

None of these |

Question 26 |

The XOR gate produces high output only when two inputs are

High | |

Low | |

Different | |

Equal |

Question 27 |

In a microprocessor, the address of next instruction to be executed is stored in

Stack pointer | |

Address latch | |

Program counter | |

Any general purpose register |

Question 28 |

The LED’s for their display require

A voltage of 1.2v and a current of 20 mA | |

A voltage of 20v and a current of 1.2 A | |

A voltage of 1.2v and current of 100 mA | |

A voltage of 10v and a current of 120 mA |

Question 29 |

Two equal voltages os same frequency applied to the X and Y plates of a CRD, produces a circle on the screen. The phase difference between the two voltages is

30 ^{o} | |

90 ^{o} | |

180 ^{o} | |

0 ^{o} |

Question 30 |

Kirchoff’s laws are applicable to

d.c. circuits only | |

a.c. circuits only | |

both a.c. and d.c. circuits | |

none of the above |

Question 31 |

The materials having low retentivity are suitable for making

Temporary magnets | |

Permanent magnets | |

Weak magnets | |

None of these |

Question 32 |

A 50KW, 3-phase, 400V, 60H induction motor runs at 1140 rpm. The % slip will be

1% | |

3% | |

5% | |

24% |

Question 33 |

Which of the following device can be used for controlling the speed of a dc motor ?

Thyratron | |

Thyristor | |

Transistor | |

Thermistor |

Question 34 |

The impulse response of an RL circuit is a

Rising exponential function | |

Decaying exponential function | |

Step function | |

Parabolic function |

Question 35 |

When the speed at which a conductor is moved through a magnetic field is increased, the induced voltage

Increases | |

Decreases | |

Remains constant | |

Reaches zero |

Question 36 |

Which of the following is the fastest analog to digital converter

Flash ADC | |

Dual slope ADC | |

Successive approximation ADC | |

Counter type ADC |

Question 37 |

Which of the following μP is a 8 bit processor ?

80286 | |

8085 | |

80386 | |

8086 |

Question 38 |

The load factor is equal to

Average load/peak load | |

Peak load/average load | |

Average load/connected load | |

Average load/base load |

Question 39 |

Open circuit test on transformer is conducted to determine

Core losses | |

Copper Losses | |

Eddy Current losses | |

Hysteresis Losses |

Question 40 |

Form factor is defined as

peak value / rms value | |

rms value / average value | |

rms value / peak value | |

average value / rms value |

Question 41 |

Given relations R(w,x) and S(y,z), the result of

SELECT DISTINCT w, x

FROM R.S is guaranteed to be same as R, if

SELECT DISTINCT w, x

FROM R.S is guaranteed to be same as R, if

R has no duplicates and S is non-empty | |

R and S have no duplicates | |

S has no duplicates and R is non-empty | |

R and S have the same number of tuples |

Question 42 |

Assume transaction A holds a shared lock R. If transaction B also requests for a shared lock on R, it will

result in a deadlock situation | |

immediately be granted | |

immediately be rejected | |

be granted as soon as it is released by A |

Question 43 |

If a variable can take only integral values from 0 to n, where n is a constant integer, then the variable can be represented as a bit-field whose width is the integral part of (the log in the answers are to the base 2)

log (n) + 1 | |

log (n-1) + 1 | |

log (n+1) + 1 | |

none of the above |

Question 44 |

Consider the function

find (int x, int y)

{return ((x < y) ? 0 : (x - y)) ; }

Let a, b be two non-negative integers. The call find {a, find(a, b)} can be used to find the

find (int x, int y)

{return ((x < y) ? 0 : (x - y)) ; }

Let a, b be two non-negative integers. The call find {a, find(a, b)} can be used to find the

maximum of a, b | |

positive difference of a, b | |

sum of a, b | |

minimum of a, b |

Question 45 |

Concurrent processes are processes that

do not overlap in time | |

overlap in time | |

are executed by a processor at the same time | |

none of the above |

Question 46 |

In a multi-user operating system, 20 requests are made to use a particular resource per hour, on an average. The probability that no requests are made in 45 minutes is

e ^{−15} | |

e ^{−5} | |

1 − e ^{ −5} | |

1 − e ^{ −10} |

Question 47 |

An FSM can be a

of finite tape length, rewinding capability and unidirectional tape movement. | |

of finite tape length, without rewinding capability and unidirectional tape movement. | |

of finite tape length, without rewinding capability and bidirectional tape movement. | |

of finite tape length, rewinding capability and bidirectional tape movement. |

Question 48 |

The major difference between a Moore and a Mealy machine is that

the output of the former depends on the present state and the current input | |

the output of the former depends only on the present state | |

the output of the former depends only on the current input | |

none of the above |

Question 49 |

Which of the following is not primitive recursive but computable ?

Carnot function | |

Riemann function | |

Bounded function | |

Ackermann function |

Question 50 |

Which of the following weights makes the complement operation easier in BCD form ?

8-4-2-1 | |

Excess-3 | |

2-4-2-1 | |

3-2-1-0 |

Question 51 |

Which of the following logic families is well suited for high-speed operation ?

TTL | |

ECL | |

MOS | |

CMOS |

Question 52 |

The total number of possible Boolean functions involving ‘n’ Boolean variables is

infinitely many | |

n ^{n} | |

n ^{2} | |

none of the above |

Question 53 |

Let a

_{n}a_{n−1}...a_{ 1}a_{ 0}be the binary representation of an integer b . The integer b is divisible by 3 ifthe number of one’s is divisible by 3 | |

the number of one’s is divisible by 3, but not by 9 | |

the number of zeroes is divisible by 3 | |

the difference of alternate sum, i.e., ( a _{0} + a_{ 2} + . ..) − ( a _{1} + a_{ 2} + . ..) is divisible by 3 |

Question 54 |

Which of the following is not a standard RS-232C signal ?

RTS | |

CTS | |

DSR | |

VDR |

Question 55 |

Start and stop bits are used in serial communication for

error detection | |

error correction | |

synchronization | |

slowing down the communication |

Question 56 |

The coefficient of x

^{ 2}in the expansion of is-405/16 | |

405/16 | |

405/128 | |

None of the above |

Question 57 |

for

x ∈ { 1, 1 } | |

x ∈ { 0,− 1 } | |

x ∈ { 1,− 1 } | |

x ∈ { 0, 3 } |

Question 58 |

Evaluate

α ^{2} + β^{ 2} + γ^{ 2} | |

α ^{2} β^{ 2} γ^{ 2}+1 | |

(α + β + γ + 1 ) ^{2} | |

α ^{2} + β^{ 2} + γ^{ 2}+1 |

Question 59 |

Given y = ln(ln

^{n}mx),dy/dx = ?nm /x ln mx | |

n /nx ln mx | |

n / x ln mx | |

m / nx ln mx |

Question 60 |

Given 2

^{x}+ 2^{ y}= 2^{ x+y}, dy/dx = ?-2 ^{y-x} | |

2 ^{x} (2 ^{y} +1)/2 ^{y} (2 ^{x} -1) | |

2 ^{x} (2 ^{y} -2)/2 ^{y} (2 ^{x} -1) | |

2 ^{x} (2 ^{y} -1)/2 ^{y} (2 ^{x} -1) |

Question 61 |

The line y = m x + c will be tangent to the ellipse x

^{2}/ 9 + y^{2}/ 4 = 1 , if c is equal to3 / m | |

√ 9m ^{2} + 4 | |

√ 1 + m ^{ 2} | |

√ 4m ^{2} + 9 |

Question 62 |

The circle x

^{ 2}+ y^{ 2}+ 2 ax + 1 = 0 (where a > 0 ) is ________.tangent to the y-axis | |

does not meet the y-axis | |

intersects the y-axis | |

intersects both x-axis and y-axis |

Question 67 |

AB is a vertical pole. The end A is on the level ground, C is the middle point of AB and P is a point on the level ground. The portion CB subtends an angle β at P. If AP = nAB, then

tan β = (n+1)/(2n ^{2}+1) | |

tan β = n/(2n ^{2}+1) | |

t an β = (n-1)/(2n ^{2}+1) | |

tan β = n / (n ^{2}+1) |

Question 68 |

There exist positive integers A, B and C, with no common factor greater than 1, such that, Alog

_{200}(5) + B log_{200}(2) = C then what is the value of A + B + C ?6 | |

7 | |

8 | |

9 |

Question 69 |

Let and are unit vectors inclined at an angle α to each other. Then, if

2π / 3 < α < π | |

α = 5π / 12 | |

α = 5π / 3 | |

α = 4π / 3 |

Question 71 |

The solution of the differential equation (dy / dx) + (y + x) = x

^{2}with y = 1 when x = 1 isx y = x ^{4} + 2 | |

2 x y = x ^{4} + 4 | |

3 x y = x ^{4} + 4 | |

4 x y = x ^{4} + 3 |

Question 72 |

The perpendicular from the origin to the line y = m x + c meets it at the point ( − 1 , 2 ) . Then, the values of m and c are

m = 3/2 , c = 5/2 | |

m = -1/2 , c = 5/2 | |

m = 1/2 , c = -5/2 | |

m = 1/2 , c = 5/2 |

Question 76 |

Complete the series by choosing the appropriate missing term from the options given.
80, 10, 70, 15, 60, ?

20 | |

25 | |

30 | |

50 |

Question 77 |

Complete the series by choosing the appropriate missing term from the options given.
664, 332, 340, 170, ?, 89

85 | |

97 | |

109 | |

178 |

Question 78 |

Complete the series by choosing the appropriate missing term from the options given.
QPO NML KJI ? EDC

HGF | |

CAB | |

JKL | |

GHI |

Question 79 |

Complete the series by choosing the appropriate missing term from the options given.
U32, V29, ?, X23, Y20.

W26 | |

W17 | |

Z17 | |

X26 |

Question 80 |

Select the related letter/word/number/figure from the given alternatives.
Book : Publisher :: Film : ?

Writer | |

Editor | |

Director | |

Producer |

Question 81 |

Select the related letter/word/number/figure from the given alternatives.
Menu : Food :: Catalogue : ?

Books | |

Library | |

Newspaper | |

Rack |

Question 82 |

Select the related letter/word/number/figure from the given alternatives.
Film : ADGH :: Milk : ?

ADGF | |

HDGE | |

HDGF | |

HEGF |

Question 83 |

Choose the most appropriate option.
One-sixth of a certain number is four more than one-twelfth the number. Find the number.

6 | |

18 | |

36 | |

48 |

There are 85 questions to complete.