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

Question # 1

During each cycle, alternating voltage reaches a peak value

One time A
Two times B
Four times C
A number of times depending on the frequency D

Question # 2

In free space, the speed of electromagnetic waves is

3 x 10⁸ms^-1 A
3 x 10⁶ms^-1 B
4 x 10⁷ms^-1 C
3 x 10⁹ms^-1 D

Question # 3

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 # 4

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 # 5

In describing functions of digital systems, a closed switch will be shown as

0 A
1 B
low C
any one of these D

Question # 6

The alternative voltage of current is actually measured by:

Its RMS value A
Square root of its mean square value B
Instantaneous value C
Peak value D
Both (A) and (B) E

Question # 7

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 # 8

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

zero A
infinity B
one C
any one of these D

Question # 9

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 # 10

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 # 11

In which of the following diodes when an electron combines with a hole during the forward biasing, photon of visible light is emitted.

photo diode A
light emitting diode B
photo voltaic cell C
all of them D

Question # 12

Conversion of alternating current into direct current is called

amplification A
rectification B
conduction C
polarization D

Question # 13

The power factor of resonant series circuit is

1 A
0 B
-1 C
0.5 D

Question # 14

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 # 15

The output voltage of half wave rectification is in the form of

a smooth curve A
a smooth wave B
pulses C
all of the above D

Question # 16

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

Capacitor A
Inductor B
D.C. motor C
Battery D

Question # 17

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 # 18

At resonance, the phase angle for RLC series resonance circuit equals

0° A
90° B
180° C
270° D

Question # 19

The magnitude of alternative voltage V:

Always increase A
Always decrease B
Remains constant C
Does not remain constant D
None of these E

Question # 20

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 # 21

A digital system deals with quantities or variables which have

only one state A
only two discrete states B
three discrete states C
four discrete states D

Question # 22

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 # 23

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

base and emitter A
collector and emitter B
base and collector C
any one of these D

Question # 24

The closed loop gain of the inverting amplifier is written as

G = R₂/R₁ A
G = 1 + R₂/R₁ B
G = -R₂/R₁ C
G = 1 - R₂/R₁ D

Question # 25

If we connect a A.C. volt meter to read A.C. voltage, It would read its:

RMS value A
Instantaneous value B
Valued average over a cycle C
Zero D
Both (B) and (C) E

Question # 26

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 # 27

The Instantaneous value of alternative current maybe:

The same as its RMS value A
Greater than its Rms value B
The same as its peak value C
Any of these D
None of these E

Question # 28

At resonance frequency the impedance of parallel resonance circuit is

Maximum A
Minimum B
Zero C
None of the above D

Question # 29

Which of the following diode is used for the detection of light

photo diode A
light emitting diode B
photo voltaic cell C
all of them D

Question # 30

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

Sr.#	Question	Answer
1	In n-p-n transistor, emitter base junction is kept	A. reversed B. forward biased C. may be reversed or may be forward biased D. none of these
2	The basic circuit elements of A.C circuit are	A. Resistor B. Inductor C. Capacitor D. All the three
3	If we connected the ordinary DC ammeter to measure alternating current, it would measure its:	A. Instantaneous value B. RMS value C. Value averaged over a cycle D. Either (B) or (C)
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 value of output resistance of OP-AMOP is of the order of	A. few ohms B. few hundred ohms C. several kilo ohms D. several mega ohms
6	The most common source of alternating voltage is:	A. Motor B. Transformer C. AC genrator D. Both (A) and (C)
7	Conversion of alternating current into direct current is called	A. amplification B. rectification C. conduction D. polarization
8	The value of the input resistance of OP-AMP is of the order of	A. few ohms B. few hundred ohms C. several kilo ohms D. several maga ohms
9	The basic circuit element in D.C. circuit is:	A. A capacitor B. A resistor C. An inductor D. Both (A) and (C)
10	A resonance curve for RLC series circuit is a plot of frequency versus	A. Voltage B. Current C. Impedance D. Reactance

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