At temperature of 298 Kelvin, Silicon is not suitable for most-electronic applications, due to small amount of conductivity. This can be altered by

By doping Germanium with Gallium, the types of semi-conductors formed are
1. N type
2. P type
3. Intrinsic
4. Extrinsic

An n-type of silicon can be formed by adding impurity of:
1. Phosphorous
2. Arsenic
3. Boron
4. Aluminum 
Which of the above are correct ?

According to Einstein’s relationship for a semiconductor, the ratio of diffusion constant to the mobility of the charge carriers is

Swept-out voltage in PIN diode happens when PIN diode is

The number of holes in an N-type silicon with intrinsic value 1.5 × 10¹⁰/cm³ and doping concentration of 10¹⁷/cm³, by using mass-action law is

A tunnel-diode is best suited for

Small recovery time of a diode is most significant for

In JFET, when operated above the pinch-off voltage, the

Thermal runaway is not possible in FET because, as the temperature of FET increases

Consider the following statements regarding an N-P-N Bipolar Junction Transistor:
1. Emitter diode is forward biased and collector diode is reverse biased
2. Emitter has many free electrons
3. Free electrons are injected into base and pass through collector
4. Depletion layers around junction J1 and J2 of BJT are widened 
    Which of the above statements are correct?

A freewheeling diode T phase controlled rectifier

The zeners incorporated within the encapsulations of some MOSFETs are meant for

When UJT is used for triggering an SCR, the wave-shape of the signal obtained from UJT circuit is

Darlington pairs are frequently used in linear ICs because, they

In a MOS capacitance fabricate on a P-type semiconductor, strong inversion occurs, when potential is

A CMOS amplifier when compared to an N channel MOSFET has the advantage of

Consider the following statements regardingoptocouplers:
1. Optocouplers are LEDs driving photodiodes in a single package to provide electrical isolation between input and output
2. Optocouplers is LED driving a phototransistor in a single package that replaces pulse transformers working at input zero crossing
3. Optocouplers are used as temporary non fixed joints between optical fibre terminations 
  Which of the above statements are correct?

Which of the following does not cause permanent damage to an SCR ?

The basic structure of an avalanche photodiode is

A five digits number is formed using the digits 1, 3, 5, 7 and 9 without repeating any of them. What is the sum of all such possible five digit numbers ?

Examples of an active display and a passive display respectively are

The dc resistivity and permeability exhibited by a type 1 superconductor are respectively

Statement (I):One of the mechanisms by which a transistor’s usefulness may be terminated, as the collector voltage is increased, is called punch through.
Statement (II): Punch through results from the increased width of the collector-junction transition region with increased collector-junction voltage

Statement (I): Conduction takes place in an enhancement MOSFET only for gate voltages below the threshold level.
Statement (II):In an enhancement MOSFET, a channel of semiconductor of the same type as the source and drain is induced in the substrate by a positive voltage applied to the gate.

Statement (I): MOSFET is a field effect transistor whose drain current is controlled by the voltage applied at the gate.
Statement (II): MOSFET is an insulated gate FET

Statement (I): All passive components can be fabricated in a single chip.
Statement (II): As opposed to discrete circuits where all components are separately inserted and connected, in an integrated circuit, they are simultaneously created on a chip of semiconductor material during manufacturing

What is an advantage of MOS transistor structure in integrated circuits?

An LTI system has a wide-sense stationary (WSS) input signal with zero mean. Its output is

In degenerately doped n conduction n-type semiconductor, the Fermi level lies in conduction band when

The purpose of connecting a Zener diode in a UJT circuit, used for triggering thyristors, is to

Statement (I):With a small additional energy, usually thermal, the valence electrons in germanium can become free electrons.
Statement (II):The valence electrons in germanium are in the fourth orbit and are at high energy level.

Statement (I): An FET is a current-controlled device.
Statement (II): Operation of an FET depends only on majority.

Statement (I): Thermal runaway is not possible in an FET.
Statement (II): As the temperature of an FET increases, the mobility of carriers decreases.

Statement (I): In an enhancement type MOSFET (with n-type source and drain regions), only positive voltage can be applied to the gate with respect to the substrate (p-type).
Statement (II): Only with a positive voltage to the gate, an ‘inversion layer’ is formed and conduction can take place

For a fully transposed transmission line         

The best device for improving the switching speeds of bipolar transistors is

The early effect in bipolar junction transistor is caused by

To get higher cut-off frequency in a BJT, base sheet resistance should be

A BJT operates as a switch

What is the biasing condition of junctions in bipolar junction transistor to work as an amplifier?

In a JFET, operating above pinch-off voltage, the

If V_cc = 18V, voltage divider resistances R₁ = 4.7 kΩ and R₂ = 1500 Ω, what is the base bias voltage?

An SCR has an anode supply of sine voltage 200V_r.m.s., 50 Hz applied through a 100 Ω resistor and fired at an angle of 60°. Assuming no voltage drop, the r.m.s. value of the output voltage is nearly

In a GTO, anode current begins to fall when gate current

An SCR is turned off when its turn-off time is

The bandwidth of a digitally recorded signal primarily depends upon

While measuring the voltage developed by a thermocouple, it is found that there is always an offset voltage. This is due to

For an antenna, radiation intensity is defined as

A source of (power/energy) feeds the input port of an amplifier and the output port is connected to a ‘load’. The input impedance of the ideal amplifier should ideally be

Medium doping in Silicon and Germanium corresponds to impurity of the order of

An electric field is applied to a semiconductor. Let the number of charge carriers be n and the average drift speed by v. If the temperature is increased then

Statement (I): Centre tap transformer is essential for a centre-tapped rectifier.
Statement (II): In half wave rectification minimum two diodes are required.

Statement (I): Power factor is a measure of the power flow in the insulator and should be low.
Statement (II): It varies with the temperature and usually increases with the rise in temperature of the insulation.

Statement (I): An SCR has a current controlled negative resistance characteristic.
Statement (II):For a given current the voltage can be determined while for a given voltage current cannot be determined.

Statement (I): JEET is operated in depletion mode only.
Statement (II): The input resistance of a MOSFET is several orders of magnitude greater than that of a JEET.

Statement (I): A photodiode is an example of a photo-conductive sensor.
Statement (II): A photodiode can be used as either a photo conductive or a photo resistive sensor.

A heavily doped semiconductor has

A Zener diode has the following properties:
1. It is properly doped crystal diode with sharp breakdown.
2. It is reverse biased
3. Its forward characteristics are just that of ordinary diode
4. Its reverse characteristics are like and ordinary diode

A tunnel diode is a p-n junction in which

Which is the diode used for measuring light intensity?

Which of the following are essentials of a transistor biasing circuit?
1. Proper zero signal collector current flow
2. V_CE should not fall below 0.5 V for Germanium and 1 V for Silicon
3. Ensure stabilization of operating point
4. Loading to the source

Which of the following options is the closet meaning to the sentence given below?

When a transistor is saturated,

If the value of a transistor changes 0.5% from its nominal value of 0.9, the percentage change in b will be

If an npn silicon transistor is operated at V_CE = 5 V and I_C = 100  and has a current gain of 100 in the CE connection, then the input resistance of this circuit will be

In a bipolar junction transistor an increase in magnitude of collector voltage increases the space-charge width at the output junction diode. This causes the effective base width to decrease. This effect is known as

Given set A ={2, 3, 4, 5} set B = {11, 12, 13, 14, 15}, two numbers are randomly selected one form each set. What is the probability if the sum of the two numbers is equals to 16?                                       

Most of the linear ICs are based on two-transistor differential amplifiers because of

When the photo resist coating (during IC fabrication) is exposed to ultraviolet light the photo resist becomes

The concentration of hole-electron pairs in pure silicon at T = 300 K is 7 × 10¹⁵ per cubic metre. Antimony is doped into silicon in a proportion of 1 atom in 10⁷ atoms. Assuming that half of the impurity atoms contribute electrons in the conduction band, the factor by which the number of charge carriers increase due to doping (the number of silicon atoms per cubic metre is 5 × 10²⁸ ) is

A potential barrier of 0.50 V exists across a p-n junction. If the depletion region is 5.0 × 10⁷ m wide, what is the intensity of the electric field in this region?

In a trans conductance, the device output

if the drift velocity of holes under a field gradient of 200 V/m is 100m/s, their mobility in SI units is

The given statement is followed by some course of action. Assuming the statement to be true, decide the correct option.
There has been a significant drop in the water level in the lakes supplying water to the city
Courses of action
I. the water supply authority should impose a partial cut in supply to tackle the situation
II. the government should appeal to all the residents through mass media for minimal use of water.
III. the government should ban the water supply in lower areas.

Hall effect is useful for the measurement of a semiconductor’s

A freewheeling diode in a phase-controlled rectifier

The relative values of the forward conduction voltage for a p-njunction diode, a Red LED and a Schottky barrier diode are

The  number of students in a class who have answered correctly, wrongly, or not attempted each question in an exam, are listed in the table given below. The marks for each question are also listed. There is no negative or partial marking. What is the average of the marks obtained by the class in the examination?

The I-V characteristics of a tunnel diode exhibit?

A gate to drain-connected enhancement mode MOSFET is an example ofx

Thermal runaway is not possible in FET because, at the temperature of FET increases

The output impedance of a BJT under common-collector configuration is

Consider the following statements related to JFET:
1.Its operation depends on the flow of minority carriers only
2.It is less noisy than BJT
3.It has poor thermal stability
4.It is relatively immune to radiation
The correct statements are

Shunt reactors are sometimes used in high voltage transmission system to

The radius of the first Bohr orbit of electrons in hydrogen atom is 0.529 Å. What is the radius of the second Bohr orbit in singly ionized helium atom?

For which one of the following materials, is the Hall coefficient closest to zero?

A 3-phase, 4-pole, self excited induction generator is feeding power to a load at a frequency f₁. If the load is partially removed the frequency becomes f₂. If the speed of the generator is maintained at 1500 rpm in both the cases, then  

The energy gap in the energy band structure of a material is 9 eV at room temperature. The material is

Consider the following statements related to piezoelectric effect:
1.It gives electrical response in terms of voltage change when mechanical stress occurs in some materials
2.It gives mechanical response in terms of dimensional change due to electrical excitation of some materials 
Which of the above statements is/are correct? 

Which of the following materials has temperature coefficient of resistivity very close to zero?

Consider an LTI system with impulse response h(t) = e^-5t u(t). if the output of the system is y(t) = e^-3t u(t) –e ^-5t u(t), then the input x(t), is given by

In a thyristor, the minimum current required to maintain the device in the ‘ON’ state is called

Which of the following magnetic materials has the highest reluctance?

The cut-off frequency of a rectangular waveguide in dominant mode is 10GHz. The width of the wave guide is

Which one of the following plays and important role in the fine recording of audio signals on magnetic tape recorder?

A resistance strain gauge with a gauge factor of 3 is fixed to a steel member subjected to a stress of 100 N/m. The Young’s modulus of steel is 2 × 10⁵ N/mm².The percentage change in resistance is

In eddy current damping system, the disc employed should be of

Which one of the following thermocouple pairs has maximum sensitivity around 273K?

Statement (I):In ferroelectric materials, domains with permanent electric dipoles may be created that would align along external electric field.
Statement (II):Ferroelectric materials undergo phase transformation of symmetric to asymmetric structure below a critical temperature.