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Online Tests
ECAT Pre General Science Physics Chapter 16 Alternating Current Online Test MCQs With Answers
Question # 1
In a transistor, the central region is called
Choose an answer
collector
emitter
base
none of them
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Question # 2
When the emitter-base junction of a transistor is reverse biased, collector current
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Reverses
Increases
Decreases
Stops
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Question # 3
The bridge circuit of full wave rectification uses
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one diode
two diode
three diode
four diode
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Question # 4
The Instantaneous value of alternative current maybe:
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The same as its RMS value
Greater than its Rms value
The same as its peak value
Any of these
None of these
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Question # 5
The circuit which is used to smooth the output voltage of the full-wave rectification is known as
Choose an answer
transformer
rectifier
filter
none of these
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Question # 6
The output voltage of half wave rectification is in the form of
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a smooth curve
a smooth wave
pulses
all of the above
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Question # 7
An A.C. voltage is applied across the inductor. When the frequency of the voltage is increased, the current
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Decreases
Increases
Does not change
Momentarily goes to zero
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Question # 8
Mathematical manipulation of the two quantized states can be best carried if they are represented by
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high - low
yes - no
on - off
0 - 1
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Question # 9
During each cycle, alternating voltage reaches a peak value
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One time
Two times
Four times
A number of times depending on the frequency
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Question # 10
The time interval during which the Voltage source changes its polarity once is known as:
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Time period T
Half the time period
Quarter the time period
Two third of the time period
None of these
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Question # 11
Nowadays, Most of the electric energy is produced by the A.C. generators using:
Choose an answer
Hydal water
Geothermal energy
Solar energy
Biomass
Both (B) and (D)
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Question # 12
The input resistance of the OP-AMP is the resistance between the
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(-) input and output
(+) input and output
(-) and (+) inputs
between any inputs
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Question # 13
Which of the following has a great concentration of impurity
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base
emitter
collector
none of these
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Question # 14
When the pn-junction is in reversed biased, current flows through the junction due to the
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majority carriers
minority carriers
either of them
none of them
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Question # 15
The phase angle of a series RLC circuit at resonance is
Choose an answer
180
°
90
°
0
°
None of the these
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Question # 16
In frequency modulation (FM), the carrier waves amplitude
Choose an answer
Remains constant
Increase
Decreases
None of these
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Question # 17
The closed loop gain of the inverting amplifier is written as
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G = R
2
/R
1
G = 1 + R
2
/R
1
G = -R
2
/R
1
G = 1 - R
2
/R
1
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Question # 18
When the p-n junction is forward biased its resistance is of the order of
Choose an answer
few mega ohms
few kilo ohms
few ohms
few milli ohms
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Question # 19
At resonance frequency the impedance of parallel resonance circuit is
Choose an answer
Maximum
Minimum
Zero
None of the above
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Question # 20
The amplifier which us used to perform mathematical operations electronically is known as
Choose an answer
calculator
OP-AMP
computer
any one of them
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Question # 21
The open loop gain of OP-AMP is of the order of
Choose an answer
10
2
10
3
10
4
10
5
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Question # 22
The wave form of alternating voltage is the graph between:
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Voltage across X-axis and time across y-axis
Current and time
Voltage along y-axis and time along x-axis
Voltage and current
Either (B) or (D)
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Question # 23
In a normally biased n-p-n transistor, an electron c current I
E
flows from the
Choose an answer
emitter into the base
collector into the base
base into collector
none of these
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Question # 24
The r.m.s. value of alternating current is equal to its maximum value at angle of
Choose an answer
60
°
45
°
30
°
90
°
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Question # 25
Peak value of alternative current is:
Choose an answer
one of its Instantaneous value
Equal to its RMS value
The same as its peak-to-peak value
Both (B) and (C)
None of these
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Question # 26
The waveform of alternating voltage is a:
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Square
Rectangular
Saw-tooth
Sinusoidal
None of these
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Question # 27
In n-p-n transistor, emitter base junction is kept
Choose an answer
reversed
forward biased
may be reversed or may be forward biased
none of these
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Question # 28
The phase at the positive peak of an A.C. cycle is:
Choose an answer
0
º
90
º
180
º
0 and
Ꮨ
Ꮨ/2 and 3
Ꮨ/2
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Question # 29
The alternative voltage of current is actually measured by:
Choose an answer
Its RMS value
Square root of its mean square value
Instantaneous value
Peak value
Both (A) and (B)
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Question # 30
In an A.C circuit with resistor only, the current and voltage have a phase angle of
Choose an answer
90
°
0
°
180
°
none of these
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Question # 31
The impedance of RLC series resonance circuit at resonant frequency is
Choose an answer
Greater than R
Equal to R
Less than R
None of these
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