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Online Tests
ECAT Pre General Science Physics Chapter 16 Alternating Current Online Test MCQs With Answers
Question # 1
Which of the following diodes can operate in the reverse biased condition
Choose an answer
photo diode
light emitting diode
photo voltaic cell
none of these
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Question # 2
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 # 3
The entire wave form of sinusoidal voltage is actually a set of all the:
Choose an answer
Positive maximum value + V
o
and negative maximum value -V
o
Posiotive maximum value +V
o
and zero
Zero and negative maximum value -V
o
Any of these
None of these
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Question # 4
The magnitude of alternative voltage V:
Choose an answer
Always increase
Always decrease
Remains constant
Does not remain constant
None of these
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Question # 5
Alternating current can be transmitted:
Choose an answer
To long distance
At very high cost
At very low cost
Both (A) and (C)
Both (A) and (B)
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Question # 6
The sum of positive and negative peak values is called:
Choose an answer
Instantaneous value
Peak value
Rms valuie
Peak-to peak-value
None of these
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Question # 7
During the negative half-cycle of the half-wave rectification, the diode
Choose an answer
does not conduct
conducts
either of these
none of these
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Question # 8
The RMS value of alternating current is:
Choose an answer
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 # 9
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 # 10
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
Choose an answer
2nd group
fourth group
fifth group
sixth group
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Question # 11
A P-N juction or semiconductor diode cannot be used as
Choose an answer
A rectifier
Detector
Oscillator
An amplifier
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Question # 12
The R
1
= infinity and R
2
= 0, then the gain of non-inverting amplifier is
Choose an answer
zero
infinity
one
any one of these
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Question # 13
Chock consumes externally small
Choose an answer
Charge
Current
Power
Potential
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Question # 14
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 # 15
Which one of the following Electro-magnetic wave have the highest frequency and shortest wave-length
Choose an answer
X-rays
Ultraviolet rays
y-rays
Cosmic rays
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Question # 16
An A.C varies as a function of
Choose an answer
Current
Voltage
Time
Charge
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Question # 17
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 # 18
Alternating current is produced by a voltage source which polarity:
Choose an answer
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 # 19
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 # 20
Which one of the following is correct?
Choose an answer
V
o
= 1.414 V
rms
I
ams
= 1.414 I
o
VO = 10.70 Vrms
Both a and b
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Question # 21
In half wave rectification
Choose an answer
both halves of the input voltage is used
only one half of the input voltage is used
either of these
none of these
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Question # 22
The bridge circuit of full wave rectification uses
Choose an answer
one diode
two diode
three diode
four diode
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Question # 23
The device which allows only the flow of an A.C. through a circuit is
Choose an answer
Capacitor
Inductor
D.C. motor
Battery
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Question # 24
The value of output resistance of OP-AMOP is of the order of
Choose an answer
few ohms
few hundred ohms
several kilo ohms
several mega ohms
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Question # 25
The highest value reached by the voltage or current:
Choose an answer
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 # 26
A signal appears after amplification, at the output terminal with a phase shift of 180
° , if it is applied at
Choose an answer
inverting input
non-inverting input
any one of the input terminal
none of them
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Question # 27
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
Choose an answer
base and emitter
collector and emitter
base and collector
any one of these
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Question # 28
For normal operation of transistor, the batteries
Choose an answer
V
CC
is of much lower value than V
BB
V
CC
is of much higher value than V
BB
V
CC is equal to
V
BB
none of these
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Question # 29
Which of the following diode is used to derive the current in external circuit when light is incident in the circuit
Choose an answer
photo diode
light emitting diode
photo voltaic cell
none of these
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Question # 30
Most OP-AMP operates with
Choose an answer
+
6 V supply
+
10 V supply
+
12 V supply
+
24 V supply
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Question # 31
If we connected the ordinary DC ammeter to measure alternating current, it would measure its:
Choose an answer
Instantaneous value
RMS value
Value averaged over a cycle
Either (B) or (C)
Either (A) or (C)
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