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

Question # 1

When the pn-junction is in reversed biased, current flows through the junction due to the

majority carriers A
minority carriers B
either of them C
none of them D

Question # 2

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 # 3

For normal operation of transistor, the batteries

V_CCis of much lower value than V_BB A
V_CCis of much higher value than V_BB B
V_{CC is equal to}V_BB C
none of these D

Question # 4

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

photo diode A
light emitting diode B
photo voltaic cell C
none of these D

Question # 5

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 # 6

Which of the following has a great concentration of impurity

base A
emitter B
collector C
none of these D

Question # 7

In n-p-n transistor, emitter base junction is kept

reversed A
forward biased B
may be reversed or may be forward biased C
none of these D

Question # 8

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 # 9

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 # 10

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 # 11

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 # 12

In a normally biased n-p-n transistor, an electron c current I_Eflows from the

emitter into the base A
collector into the base B
base into collector C
none of these D

Question # 13

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 # 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 closed loop gain of the non-inverting amplifier is given by

G = R₂/R₁ A
G = -R₂/R₁ B
G = 1 - R₂/R₁ C
G = 1 + T₂/R₁ D

Question # 16

In frequency modulation (FM), the carrier waves amplitude

Remains constant A
Increase B
Decreases C
None of these D

Question # 17

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

photo diode A
light emitting diode B
photo voltaic cell C
none of these D

Question # 18

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 # 19

The input resistance of the OP-AMP is the resistance between the

(-) input and output A
(+) input and output B
(-) and (+) inputs C
between any inputs D

Question # 20

Nowadays, Most of the electric energy is produced by the A.C. generators using:

Hydal water A
Geothermal energy B
Solar energy C
Biomass D
Both (B) and (D) E

Question # 21

Average value of A.C voltage during one cycle is

1 A
Zero B
Maximum C
Variable D

Question # 22

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 # 23

When the pn-junction is connected reversed biased, its resistance is of the order of

few ohms A
few kilo-ohms B
few mega-ohms C
few mili-ohms D

Question # 24

At resonance, the impedance of RLC series circuit is

Maximum A
Zero B
Minimum C
Determinate D

Question # 25

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 # 26

The phase at the positive peak of an A.C. cycle is:

0º
A
90º
B
180º
C
0 andᏘ D
Ꮨ/2 and 3Ꮨ/2 E

Question # 27

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 # 28

At higher frequency of the alternating current, the capacitive reactance X_c

Increases A
Decreases B
Remains the same C
Increases only when the voltage increases D

Question # 29

In an A.C circuit with resistor only, the current and voltage have a phase angle of

90° A
0° B
180° C
none of these D

Question # 30

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

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

Sr.#	Question	Answer
1	Which of the following diode is used to derive the current in external circuit when light is incident in the circuit	A. photo diode B. light emitting diode C. photo voltaic cell D. none of these
2	An A.C. voltage is applied across the inductor. When the frequency of the voltage is increased, the current	A. Decreases B. Increases C. Does not change D. Momentarily goes to zero
3	The device which allows only the flow of an A.C. through a circuit is	A. Capacitor B. Inductor C. D.C. motor D. Battery
4	In free space, the speed of electromagnetic waves is	A. 3 x 10⁸ms^-1 B. 3 x 10⁶ms^-1 C. 4 x 10⁷ms^-1 D. 3 x 10⁹ms^-1
5	When the pn-junction is connected reversed biased, its resistance is of the order of	A. few ohms B. few kilo-ohms C. few mega-ohms D. few mili-ohms
6	Mathematical manipulation of the two quantized states can be best carried if they are represented by	A. high - low B. yes - no C. on - off D. 0 - 1
7	The length of rotating vector (on a certain scale) represents the:	A. Peak value of alternating quantity B. RMS value of alternating quantity C. Instantaneous value of alternating quantity D. Either (B) or (C)
8	When the pn-junction is forward biased. the current flows through it is of the order of	A. mili-amperes B. amperes C. nano-amperes D. micro-amperes
9	The impedance of RLC series resonance circuit at resonant frequency is	A. Greater than R B. Equal to R C. Less than R D. None of these
10	OP-AMP has the following input terminals	A. one B. two C. three D. four

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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