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

Question # 1

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 # 2

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 # 3

The value of current gain of n-p-n transistor is of the order of

tens A
hundreds B
thousands C
ten thousands D

Question # 4

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

calculator A
OP-AMP B
computer C
any one of them D

Question # 5

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 # 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

The sum of positive and negative peak values is called:

Instantaneous value A
Peak value B
Rms valuie C
Peak-to peak-value D
None of these E

Question # 8

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 # 9

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

2nd group A
fourth group B
fifth group C
sixth group D

Question # 10

In a transistor, the central region is called

collector A
emitter B
base C
none of them D

Question # 11

The basic circuit elements of A.C circuit are

Resistor A
Inductor B
Capacitor C
All the three 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

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 # 14

A diode characteristic curve is a plot between

current and time A
voltage and time B
voltage and current C
forward voltage and reversed voltage 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

The power factor of resonant series circuit is

1 A
0 B
-1 C
0.5 D

Question # 17

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

0° A
90° B
180° C
270° D

Question # 18

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 # 19

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 # 20

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

few mega ohms A
few kilo ohms B
few ohms C
few milli ohms D

Question # 21

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

inverting input A
non-inverting input B
any one of the input terminal C
none of them D

Question # 22

The phase angle of a series RLC circuit at resonance is

180° A
90° B
0° C
None of the these D

Question # 23

If the value of C in a series RLC circuit is increased, the resonant frequency

Is not affected A
Increase B
Remains the same C
Decreases D

Question # 24

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

Voltage A
Current B
Impedance C
Reactance D

Question # 25

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 # 26

The bridge circuit of full wave rectification uses

one diode A
two diode B
three diode C
four diode D

Question # 27

The length of rotating vector (on a certain scale) represents the:

Peak value of alternating quantity A
RMS value of alternating quantity B
Instantaneous value of alternating quantity C
Either (B) or (C) D
Either (A) or (B) E

Question # 28

An A.C varies as a function of

Current A
Voltage B
Time C
Charge D

Question # 29

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 # 30

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

Sr.#	Question	Answer
1	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
2	If 250V is the RMS value of alternative voltage, then its peak value V_owill be:	A. 353.5V B. 250V C. 175V D. zero
3	The value of current gain of n-p-n transistor is of the order of	A. tens B. hundreds C. thousands D. ten thousands
4	Alternating current can be transmitted:	A. To long distance B. At very high cost C. At very low cost D. Both (A) and (C)
5	During each cycle, alternating voltage reaches a peak value	A. One time B. Two times C. Four times D. A number of times depending on the frequency
6	Which of the following diodes can operate in the reverse biased condition	A. photo diode B. light emitting diode C. photo voltaic cell D. none of these
7	Alternating current is produced by a voltage source which polarity:	A. Remains the same B. Reverse after period T C. Keeps on reversing with time D. Reverse after every time interval T/2
8	In RLC series circuit, resonance occurs when	A. X_{L > Xc} B. X_{L < Xc} C. X_{L = Xc} D. None of these
9	The R₁= infinity and R₂= 0, then the gain of non-inverting amplifier is	A. zero B. infinity C. one D. any one of these
10	In series RC circuit when R=X_c, then the phase angle is	A. 0° B. 90° C. 70° D. 45°

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