Question # 1

Which of the following diodes can operate in the reverse biased condition

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photo diode

light emitting diode

photo voltaic cell

none of these

The emitter-base junction of a transistor is forward-biased and collector-base junction is reverse-biased. If the base current is increased, its

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I_cwill decrease

V_CEwill increase

I_Cwill increase

V_CCwill increase

The entire wave form of sinusoidal voltage is actually a set of all the:

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Positive maximum value + V_oand negative maximum value -V_o

Posiotive maximum value +V_oand zero

Zero and negative maximum value -V_o

Any of these

None of these

The magnitude of alternative voltage V:

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Always increase

Always decrease

Remains constant

Does not remain constant

None of these

Alternating current can be transmitted:

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To long distance

At very high cost

At very low cost

Both (A) and (C)

Both (A) and (B)

The sum of positive and negative peak values is called:

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Instantaneous value

Peak value

Rms valuie

Peak-to peak-value

None of these

During the negative half-cycle of the half-wave rectification, the diode

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does not conduct

conducts

either of these

none of these

The RMS value of alternating current is:

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0.7 times at the peak value

0.5 times the peak value

0.7 times the Instantaneous value

Equal to maximum voltage

None of these

The amplifier which us used to perform mathematical operations electronically is known as

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calculator

OP-AMP

computer

any one of them

A p-n junction is formed when a crystal of silicon is growth in such a way that its one half is doped with trivalent impurity and the other half with a impurity from

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2nd group

fourth group

fifth group

sixth group

A P-N juction or semiconductor diode cannot be used as

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A rectifier

Detector

Oscillator

An amplifier

The R₁= infinity and R₂= 0, then the gain of non-inverting amplifier is

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zero

infinity

one

any one of these

Chock consumes externally small

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Charge

Current

Power

Potential

The r.m.s. value of alternating current is equal to its maximum value at angle of

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60°

45°

30°

90°

Which one of the following Electro-magnetic wave have the highest frequency and shortest wave-length

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X-rays

Ultraviolet rays

y-rays

Cosmic rays

An A.C varies as a function of

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Current

Voltage

Time

Charge

When the p-n junction is forward biased its resistance is of the order of

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few mega ohms

few kilo ohms

few ohms

few milli ohms

Alternating current is produced by a voltage source which polarity:

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Remains the same

Reverse after period T

Keeps on reversing with time

Reverse after every time interval T/2

Both (C) and (D)

In free space, the speed of electromagnetic waves is

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3 x 10⁸ms^-1

3 x 10⁶ms^-1

4 x 10⁷ms^-1

3 x 10⁹ms^-1

Which one of the following is correct?

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V_o= 1.414 V_rms

I_ams= 1.414 I_o

VO = 10.70 Vrms

Both a and b

In half wave rectification

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both halves of the input voltage is used

only one half of the input voltage is used

either of these

none of these

The bridge circuit of full wave rectification uses

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one diode

two diode

three diode

four diode

The device which allows only the flow of an A.C. through a circuit is

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Capacitor

Inductor

D.C. motor

Battery

The value of output resistance of OP-AMOP is of the order of

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few ohms

few hundred ohms

several kilo ohms

several mega ohms

The highest value reached by the voltage or current:

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In quarter cycle is called Instantaneous value

In half cycle is called peak-to-peak value

In one cycle is called peak value

In half cycle is called Instantaneous value

None of these

A signal appears after amplification, at the output terminal with a phase shift of 180° , if it is applied at

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inverting input

non-inverting input

any one of the input terminal

none of them

When a transistor is used as a switch the circuit in which the current is to be switched OFF and ON, is connected between the

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base and emitter

collector and emitter

base and collector

any one of these

For normal operation of transistor, the batteries

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V_CCis of much lower value than V_BB

V_CCis of much higher value than V_BB

V_{CC is equal to}V_BB

none of these

Which of the following diode is used to derive the current in external circuit when light is incident in the circuit

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photo diode

light emitting diode

photo voltaic cell

none of these

Most OP-AMP operates with

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+ 6 V supply

+ 10 V supply

+ 12 V supply

+ 24 V supply

If we connected the ordinary DC ammeter to measure alternating current, it would measure its:

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Instantaneous value

RMS value

Value averaged over a cycle

Either (B) or (C)

Either (A) or (C)

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