ECAT Pre General Science Chapter 16 online mcq test with answers for Physics chapter 16 (Alternating Current)

Question # 1

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

A rectifier A
Detector B
Oscillator C
An amplifier D

Question # 2

To design a resonant circuit of frequency 100 KHz with an inductor of inductance 5 mH, we need a capacitor of capacitance

5.07 pF A
50 pF B
0.507 pF C
507 pF D

Question # 3

Average value of A.C voltage during one cycle is

1 A
Zero B
Maximum C
Variable D

Question # 4

An A.C. voltage is applied across the inductor. When the frequency of the voltage is increased, the current

Decreases A
Increases B
Does not change C
Momentarily goes to zero D

Question # 5

Electromagnetic waves transmit energy equal to

1/2 mv² A
m_oc² B
hf/c C
hf D

Question # 6

In half wave rectification

both halves of the input voltage is used A
only one half of the input voltage is used B
either of these C
none of these D

Question # 7

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

60° A
45° B
30° C
90° D

Question # 8

Due to the high value of the input resistance, practically, the value of the current which flows between the input terminals is

zero A
small B
large C
very large D

Question # 9

The time interval during which the Voltage source changes its polarity once is known as:

Time period T A
Half the time period B
Quarter the time period C
Two third of the time period D
None of these E

Question # 10

The highest value reached by the voltage or current:

In quarter cycle is called Instantaneous value A
In half cycle is called peak-to-peak value B
In one cycle is called peak value C
In half cycle is called Instantaneous value D
None of these E

Question # 11

Which one of the following waves belongs to electromagnetic spectrum

Radio and TV waves A
Radar waves B
Micro waves C
All of them D

Question # 12

For the normal operation of the transistor, its

emitter-base and collector base junctions are forward biased A
emitter-base junction is reversed biased and collector base junction is forward biased B
emitter-base junction is forward biased and collector-base junction is reverse biased C
any one of these D

Question # 13

When the pn-junction is forward biased. the current flows through it is of the order of

mili-amperes A
amperes B
nano-amperes C
micro-amperes D

Question # 14

Alternating current can induce voltage because it has a

High peak value A
Varying magnetic field B
Stronger field than direct curren C
Constant magnetic field D

Question # 15

A sinusoidally alternating voltage or current can be graphically represented by a:

Vector A
Rotating vector B
Clockwise vector C
Anticlockwise voltage vector D
None of these E

Question # 16

The basic circuit element in A.C. circuits are:

Resistor and capacitor A
Resistor and Inductor B
Capacitor only C
Both (B) and (C) D
None of these E

Question # 17

In a transistor, if the central region is p-type then this type of transistor is known as

p-n-p transistor A
n-p-n transistor B
either of these C
none of these D

Question # 18

Unless stated otherwise, when we speak of A.C. meter reading, we usualy mean:

Peak value A
RMS value B
Instantaneous value C
Peak-to-peak value D
Both (A) and (C0 E

Question # 19

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

does not conduct A
conducts B
either of these C
none of these D

Question # 20

The basic circuit element in D.C. circuit is:

A capacitor A
A resistor B
An inductor C
Both (A) and (C) D
Both (A) and (B) E

Question # 21

In RLC series circuit, resonance occurs when

X_{L > Xc} A
X_{L < Xc} B
X_{L = Xc} C
None of these D

Question # 22

At resonance frequency the impedance of parallel resonance circuit is

Maximum A
Minimum B
Zero C
None of the above D

Question # 23

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

few ohms A
few hundred ohms B
several kilo ohms C
several mega ohms D

Question # 24

The RMS value of alternating current is:

0.7 times at the peak value A
0.5 times the peak value B
0.7 times the Instantaneous value C
Equal to maximum voltage D
None of these E

Question # 25

Most OP-AMP operates with

+ 6 V supply A
+ 10 V supply B
+ 12 V supply C
+ 24 V supply D

Question # 26

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

Instantaneous value A
RMS value B
Value averaged over a cycle C
Either (B) or (C) D
Either (A) or (C) E

Question # 27

Alternating current is produced by a voltage source which polarity:

Remains the same A
Reverse after period T B
Keeps on reversing with time C
Reverse after every time interval T/2 D
Both (C) and (D) E

Question # 28

A changing magnetic flux creates around itself

An electromotive force A
An electric field (changing electric flux) B
Magnetic field C
None of the above D

Question # 29

The waveform of alternating voltage is a:

Square A
Rectangular B
Saw-tooth C
Sinusoidal D
None of these E

Question # 30

A resonance curve for RLC series circuit is a plot of frequency versus

Voltage A
Current B
Impedance C
Reactance D

Sr.#	Question	Answer
1	Chock consumes externally small	A. Charge B. Current C. Power D. Potential
2	When the emitter-base junction of a transistor is reverse biased, collector current	A. Reverses B. Increases C. Decreases D. Stops
3	The sum of positive and negative peak values is called:	A. Instantaneous value B. Peak value C. Rms valuie D. Peak-to peak-value
4	Unless stated otherwise, when we speak of A.C. meter reading, we usualy mean:	A. Peak value B. RMS value C. Instantaneous value D. Peak-to-peak value
5	The input resistance of the OP-AMP is the resistance between the	A. (-) input and output B. (+) input and output C. (-) and (+) inputs D. between any inputs
6	The highest value reached by the voltage or current:	A. In quarter cycle is called Instantaneous value B. In half cycle is called peak-to-peak value C. In one cycle is called peak value D. In half cycle is called Instantaneous value
7	The basic circuit elements of A.C circuit are	A. Resistor B. Inductor C. Capacitor D. All the three
8	Which one of the following waves belongs to electromagnetic spectrum	A. Radio and TV waves B. Radar waves C. Micro waves D. All of them
9	The r.m.s. value of alternating current is equal to its maximum value at angle of	A. 60° B. 45° C. 30° D. 90°
10	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	A. 2nd group B. fourth group C. fifth group D. sixth group

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ECAT Pre General Science Physics Chapter 16 MCQ Test With Answer

MCQ's Test For ECAT Pre General Science Physics Chapter 16 Alternating Current

ECAT Pre General Science Physics Chapter 16 Alternating Current