## NIELIT Technical Assistant_2016_march

 Question 1
The thermionic emission current is given by
 A maxwell’s equation B Fermi-Dirac distribution C Langmuir child law D Richardson Dushman equation
 Question 2
Zener breakdown occurs
 A due to rupture of covalent bonds B due to thermally generated minority carriers C in lightly doped junctions D only in germanium diodes
 Question 3
Negative feedback in an amplifier
 A increase noise B reduce bandwidth C reduce gain D increase distortion
 Question 4
The gain of a bipolar transistor drops at high frequencies because of
 A early effect B parasitic inductive elements C high current in base D transistor capacitance
 Question 5
The main application of enhancement mode MOSFET is in
 A oscillator circuits B amplifier circuits C clipper circuit D switching circuits
 Question 6
Transducer is a device which
 A amplifies a given electrical signal B transfer an electrical signal from one place to another C translates a physical parameter into suitable electrical quantity D 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 ?
 A 800 ohm B 4 k ohm C 8 k ohm D 16 k ohm
 Question 8
N-channel FETs are considered better than p-channel FETs because
 A they consume less power B they have high switching time C mobility of electrons is greater than that of holes D 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
 A 32 k ohm B 15 k ohm C 64 k ohm D 2 k ohm
 Question 10
In a digital circuit, the clock is a
 A Flip-clop B Inverter C Monostable multivibrator D Free running multivibrator
 Question 11
In which of the following codes the successive numbers differ in only one bit position ?
 A ASCII B Gray Code C Excess-3 Code D BCD
 Question 12
An instruction used to set the carry flag in a computer can be classified as
 A data transfer B arithmetic C logical D program control
 Question 13
In FM modulation pre-emphasis is done for
 A low frequency components B high frequency components C middle frequency components D all frequency components
 Question 14
When modulation index of AM wave is increased from 0.5 to 1, the transmitted power
 A increases by 25% B increases by 33.3% C increases by 50% D remains same
 Question 15
The electric flux and field intensity inside a conducting sphere is
 A Minimum B Maximum C Uniform D Zero
 Question 16
A waveguide behaves as
 A high pass filter B low pass filter C band pass filter D all pass filter
 Question 17
In a lossless RLC circuit the transient current is
 A sinusoidal B square wave C triangular wave D non-oscillating
 Question 18
In an ac circuit, the maximum and minimum values of power factor can be
 A 10 and 1 B 1 and -1 C 1 and 0 D Any positive value
 Question 19
In a circuit containing a complex impedance, maximum power transfer takes place when load is
 A pure resistance B equal to complex impedance C conjugate complex of the circuit impedance D inductive
 Question 20
The effect of doping intrinsic semiconductor is to
 A Move the Fermi level away from the centre of forbidden band B Move the Fermi level towards the centre of forbidden band C Change the crystal structure of the semiconductor D To keep the Fermi level at the middle of the forbidden band
 Question 21
Field Effect Transistor has
 A Large input impedance B