Test Set 1 - Previous Year Questions

Question 1

If the voltage applied across a capacitance is triangular in waveform, the waveform of the current is:

A. Triangular

B. Trapezoidal

C. Sinusoidal

D. Rectangular

Question 2

Which statement is true for the relative dielectric constant?

A. It is dimensionless

B. It is not equal to unity for vacuum

C. Its value for all substances is less than one

D. None of the above

Question 3

Pure metals generally have:

A. High conductivity and low temperature coefficient

B. High conductivity and large temperature coefficient

C. Low conductivity and zero temperature coefficient

D. Low conductivity and high temperature coefficient

Question 4

A superconductor is:

A. A material showing perfect conductivity and Meissner effect below a critical temperature

B. A conductor having zero resistance

C. A perfect conductor with highest diamagnetic susceptibility

D. A perfect conductor which becomes resistive when the current density exceeds a critical value

Question 5

The location of a lightning arrestor is:

A. Near the transformer

B. Near the circuit breaker

C. Away from the transformer

D. None of the above

Question 6

The time constant of an RC circuit increases if the resistance is:

A. Increased

B. Decreased

C. Neither a nor b

D. Both a and b

Question 7

Intrinsic semiconductors are those which:

A. Are available locally

B. Are made of the semiconductor material in its purest form

C. Have more electrons than holes

D. Have zero energy gaps

Question 8

The primary control on drain current in a JFET is exerted by:

A. Channel resistance

B. Size of depletion regions

C. Voltage drop across channel

D. Gate reverse bias

Question 9

When biased correctly, a zener diode:

A. Acts as a fixed resistance

B. Has a constant voltage across it

C. Has a constant current passing through it

D. Never overheats

Question 10

The DC current amplification factor (alpha_dc) is given by:

A. IC/IE

B. IC/IB

C. IB/IC

D. IE/IB

Question 11

Compared to bipolar transistors, FETs have:

A. High input impedance

B. Low input impedance

C. Same input impedance

D. None of the above

Question 12

A DIAC is equivalent to:

A. A pair of SCRs

B. A pair of four-layer SCRs

C. A diode and two resistors

D. A TRIAC

Question 13

The statement 'In any network of linear impedances, the current at any point equals the algebraic sum of currents caused by each source taken separately with all other emfs reduced to zero' represents:

A. Kirchhoff's law

B. Norton's theorem

C. Thevenin's theorem

D. Superposition theorem

Question 14

Which mode of a circular cylindrical waveguide has the characteristic that attenuation decreases as frequency increases, making it attractive at microwave frequencies?

A. TE1 mode

B. TM01 mode

C. TE01 mode

D. Higher order mode

Question 15

A two-port network is symmetrical if:

A. z11 z22 - z12 z21 = 1

B. h11 h22 - h12 h21 = 1

C. AD - BC = 1

D. y11 y22 - y12 y21 = 1

Question 16

For transmission line load matching over a range of frequencies, it is best to use a:

A. Balun

B. Broad band directional coupler

C. Double stub

D. Single stub of adjustable position

Question 17

The frequency modulated (FM) radio frequency range is nearly:

A. 250-300 MHz

B. 150-200 MHz

C. 88-108 MHz

D. 30-70 MHz

Question 18

In an underground cable, distortion in the transmission of carrier frequency can be eliminated by using:

A. Inductive loading

B. Resistive loading

C. Capacitive loading

D. Shielding

Question 19

The characteristic impedance of a lossless transmission line with L = 0.294 microH/m and C = 60 pF/m is approximately:

A. 49 ohms

B. 60 ohms

C. 70 ohms

D. 140 ohms

Question 20

For a quarter-wavelength lossless transmission line of characteristic impedance 50 ohms and load impedance 100 ohms, the input impedance is:

A. 25 ohms

B. 50 ohms

C. 100 ohms

D. 150 ohms

Question 21

One instrument type which is an electrometer is:

A. Electrodynamometer

B. PMMC

C. Electrostatic

D. Moving iron

Question 22

When an AC current of 5 A (rms) and a DC current of 5 A flow simultaneously through a circuit, which statement is true?

A. An AC ammeter will read less than 10 A but more than 5 A

B. An AC ammeter will read only 5 A

C. A DC ammeter will read 10 A

D. A DC ammeter will read zero

Question 23

A memoryless system is:

A. Causal

B. Not causal

C. Nothing can be said

D. None

Question 24

An air capacitor is a:

A. Time variant device

B. Active device

C. Time invariant device (only)

D. Time invariant and passive device

Question 25

Thermistors are made of:

A. Pure metals

B. Pure insulators

C. Sintered mixtures of metallic oxides

D. Pure semiconductor

Question 26

A Pirani gauge is used to measure:

A. Very low pressures

B. High pressures

C. Pressures in the region of 1 atm

D. Fluid flow

Question 27

Which circuit converts input power at one frequency to output power at a different frequency through single-stage conversion?

A. AC voltage controllers

B. Cycloconverters

C. Phase controlled rectifiers

D. Inverters

Question 28

In forward voltage triggering, a thyristor changes from:

A. Off state to on state

B. On state to off state

C. On state to on state

D. Off state to off state

Question 29

A four-quadrant operation requires:

A. Two full converters in series

B. Two full converters connected back to back

C. Two full converters connected in parallel

D. Two semi-converters connected back to back

Question 30

For a single-phase half-bridge inverter with output amplitude Vs and output power P, the corresponding values for a single-phase full-bridge inverter are:

A. Vs, P

B. Vs/2, P

C. 2Vs, 2P

D. 2Vs, P

Question 31

The energy gap in a semiconductor:

A. Increases with temperature

B. Remains constant

C. Slightly increases with temperature

D. Decreases with temperature

Question 32

In an electronic circuit, matching means:

A. Connecting a high impedance directly to a low impedance

B. Selection of components which are compatible

C. Transferring maximum amount of signal between different kinds of circuits

D. RC coupled stages

Question 33

P-channel FETs are less superior than N-channel FETs because:

A. They have higher input impedance

B. They have high switching time

C. They consume less power

D. Mobility of electrons is greater than that of holes

Question 34

The effect of a small increase in temperature on a CE-connected transistor is:

A. Increase in ICEO

B. Increase in AC current gain

C. Decrease in AC current gain

D. Increase in output resistance

Question 35

An amplifier with negative feedback:

A. Lowers its lower 3 dB frequency

B. Raises its upper 3 dB frequency

C. Increases its bandwidth

D. All of the above

Question 36

The main disadvantage of Diode-Transistor Logic (DTL) is its:

A. Greater speed

B. Slower speed

C. Average speed

D. None of the above

Question 37

The basic memory cell of dynamic RAM consists of:

A. A flip-flop

B. A transistor acting as a capacitor

C. A transistor

D. A capacitor (with an access transistor)

Question 38

The 2's complement of the binary number 1000 is:

A. 0111

B. 0101

C. 1000

D. 0001

Question 39

A master-slave flip-flop is made up of:

A. Two flip-flops connected in series

B. Two flip-flops connected in parallel

C. A debouncer circuit

D. A D-latch

Question 40

The number of nibbles making one byte is:

A. 2

B. 4

C. 8

D. 16

Question 41

The intrinsic impedance of free space:

A. Is independent of frequency

B. Decreases with increase of frequency

C. Increases with increase of frequency

D. Varies as square root of frequency

Question 42

Geosynchronous satellites are launched in the equatorial plane because it is the only plane which provides:

A. 24-hour orbit

B. Stationary satellite (relative to Earth)

C. Global communication

D. Zero-gravity environs

Question 43

Radio broadcasting is an example of:

A. Space multiplexing

B. Time multiplexing

C. Frequency multiplexing

D. None of the above

Question 44

The most common modulation system used for telegraphy is:

A. Frequency shift keying

B. Two-tone modulation

C. Pulse code modulation

D. Single-tone modulation

Question 45

Use of a varactor diode in generation of a modulated signal is for:

A. FM generation only

B. AM generation only

C. PM generation only

D. Both PM and AM generation

Question 46

The bandwidth of microwaves is approximately:

A. 1 GHz - 1000 GHz

B. 1 GHz - 100 GHz

C. 1 GHz - 10 GHz

D. 1 GHz - 10^6 GHz

Question 47

In Transverse Magnetic (TM) mode:

A. No electric field component is in the direction of propagation

B. No magnetic field component is in the direction of propagation

C. Both magnetic and electric fields are in the direction of propagation

D. Neither magnetic nor electric fields are in the direction of propagation

Question 48

A varactor diode has non-linearity of:

A. Capacitance

B. Inductance

C. Resistance

D. It is a linear device

Question 49

Noise figure is calculated as:

A. Input S/N ratio x Output S/N ratio

B. Input S/N ratio / Output S/N ratio

C. (Input S/N ratio / Output S/N ratio) x 100

D. Input S/N ratio + Output S/N ratio

Question 50

You can quickly determine the effect of adding poles and zeros by using:

A. Nichols chart

B. Nyquist plot

C. Bode plot

D. Root locus

Question 51

A satellite link uses different frequencies for receiving and transmitting in order to:

A. Avoid interference from terrestrial microwave links

B. Avoid interference between its powerful transmitted signal and weak incoming signal

C. Minimize free-space losses

D. Maximize antenna gain

Question 52

The first determining factor in selecting a satellite system is its:

A. EIRP

B. Antenna size

C. Coverage area

D. Antenna gain

Question 53

Equalizing pulses in television are sent during:

A. Horizontal blanking

B. Vertical blanking

C. The serrations

D. The horizontal retrace