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Online Tests
ECAT Pre General Science Physics Chapter 16 Alternating Current Online Test MCQs With Answers
Question # 1
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 # 2
In half wave rectification
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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 # 3
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 # 4
Nowadays, Most of the electric energy is produced by the A.C. generators using:
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Hydal water
Geothermal energy
Solar energy
Biomass
Both (B) and (D)
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Question # 5
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 # 6
During the positive half-cycle in the half-wave rectification,the diode
Choose an answer
does not conduct
conducts
either of these
neither of these
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Question # 7
When either L or C is increased, the resonant frequency of the RLC series circuit
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Increases
Decreases
Remains the same
Becomes zero
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Question # 8
The value of the input resistance of OP-AMP is of the order of
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few ohms
few hundred ohms
several kilo ohms
several maga ohms
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Question # 9
To design a resonant circuit of frequency 100 KHz with an inductor of inductance 5 mH, we need a capacitor of capacitance
Choose an answer
5.07 pF
50 pF
0.507 pF
507 pF
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Question # 10
The length of rotating vector (on a certain scale) represents the:
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Peak value of alternating quantity
RMS value of alternating quantity
Instantaneous value of alternating quantity
Either (B) or (C)
Either (A) or (B)
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Question # 11
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 # 12
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 # 13
The closed loop gain of the non-inverting amplifier is given by
Choose an answer
G = R
2
/R
1
G = -R
2
/R
1
G = 1 - R
2
/R
1
G = 1 + T
2
/R
1
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Question # 14
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 # 15
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 # 16
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 # 17
Unless stated otherwise, when we speak of A.C. meter reading, we usualy mean:
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Peak value
RMS value
Instantaneous value
Peak-to-peak value
Both (A) and (C0
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Question # 18
SI unit of impedance is
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hertz
henry
ampere
ohms
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Question # 19
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 # 20
Which one of the following waves belongs to electromagnetic spectrum
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Radio and TV waves
Radar waves
Micro waves
All of them
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Question # 21
In which of the following diodes when an electron combines with a hole during the forward biasing, photon of visible light is emitted.
Choose an answer
photo diode
light emitting diode
photo voltaic cell
all of them
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Question # 22
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 # 23
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 # 24
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 # 25
A digital system deals with quantities or variables which have
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only one state
only two discrete states
three discrete states
four discrete states
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Question # 26
The most common source of alternating voltage is:
Choose an answer
Motor
Transformer
AC genrator
Both (A) and (C)
Both (A) and (B)
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Question # 27
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 # 28
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 # 29
For a n-p-n transistor, the conventional current equation can be written as
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I
E
+ I
C
= I
B
I
C
- I
B
= I
E
I
C
+ I
B
= I
E
I
B
+ I
E
= I
C
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Question # 30
If we connect a A.C. volt meter to read A.C. voltage, It would read its:
Choose an answer
RMS value
Instantaneous value
Valued average over a cycle
Zero
Both (B) and (C)
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Question # 31
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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