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Online Tests
ECAT Pre General Science Physics Chapter 16 Alternating Current Online Test MCQs With Answers
Question # 1
Due to the high value of the input resistance, practically, the value of the current which flows between the input terminals is
Choose an answer
zero
small
large
very large
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Question # 2
When the p-n junction is forward biased its resistance is of the order of
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few mega ohms
few kilo ohms
few ohms
few milli ohms
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Question # 3
The R
1
= infinity and R
2
= 0, then the gain of non-inverting amplifier is
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zero
infinity
one
any one of these
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Question # 4
In a transistor, if the central region is n-type, then this type of transistor is known as
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n-p-n transistor
p-n-p transistor
either of these
none of these
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Question # 5
Alternating current is produced by a voltage source which polarity:
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Remains the same
Reverse after period T
Keeps on reversing with time
Reverse after every time interval T/2
Both (C) and (D)
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Question # 6
The highest value reached by the voltage or current:
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In quarter cycle is called Instantaneous value
In half cycle is called peak-to-peak value
In one cycle is called peak value
In half cycle is called Instantaneous value
None of these
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Question # 7
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 # 8
If the value of C in a series RLC circuit is increased, the resonant frequency
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Is not affected
Increase
Remains the same
Decreases
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Question # 9
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 # 10
In a transistor, if the central region is p-type then this type of transistor is known as
Choose an answer
p-n-p transistor
n-p-n transistor
either of these
none of these
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Question # 11
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 # 12
To design a resonant circuit of frequency 100 KHz with an inductor of inductance 5 mH, we need a capacitor of capacitance
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5.07 pF
50 pF
0.507 pF
507 pF
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Question # 13
Which of the following diode is used for the detection of light
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photo diode
light emitting diode
photo voltaic cell
all of them
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Question # 14
During the positive half-cycle in the half-wave rectification,the diode
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does not conduct
conducts
either of these
neither of these
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Question # 15
A resonance curve for RLC series circuit is a plot of frequency versus
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Voltage
Current
Impedance
Reactance
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Question # 16
The magnitude of alternative voltage V:
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Always increase
Always decrease
Remains constant
Does not remain constant
None of these
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Question # 17
A signal appears after amplification, at the output terminal with a phase shift of 180
° , if it is applied at
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inverting input
non-inverting input
any one of the input terminal
none of them
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Question # 18
The emitter-base junction of a transistor is forward-biased and collector-base junction is reverse-biased. If the base current is increased, its
Choose an answer
I
c
will decrease
V
CE
will increase
I
C
will increase
V
CC
will increase
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Question # 19
When the pn-junction is forward biased. the current flows through it is of the order of
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mili-amperes
amperes
nano-amperes
micro-amperes
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Question # 20
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 # 21
The RMS value of alternating current is:
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0.7 times at the peak value
0.5 times the peak value
0.7 times the Instantaneous value
Equal to maximum voltage
None of these
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Question # 22
Most OP-AMP operates with
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+
6 V supply
+
10 V supply
+
12 V supply
+
24 V supply
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Question # 23
SI unit of impedance is
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hertz
henry
ampere
ohms
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Question # 24
The phase angle of a series RLC circuit at resonance is
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180
°
90
°
0
°
None of the these
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Question # 25
In series RC circuit when R=X
c
, then the phase angle is
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0
°
90
°
70
°
45
°
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Question # 26
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 # 27
An A.C. voltmeter read 250 volts. The frequency of alternating is 50 Hz, the peak value of voltage is
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3525.0 volts
35.35 volts
353.5 volts
3.535 volts
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Question # 28
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
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2nd group
fourth group
fifth group
sixth group
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Question # 29
OP-AMP has the following input terminals
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one
two
three
four
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Question # 30
In free space, the speed of electromagnetic waves is
Choose an answer
3 x 10
8
ms
-1
3 x 10
6
ms
-1
4 x 10
7
ms
-1
3 x 10
9
ms
-1
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Question # 31
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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