Alternating current MCQ Questions Class 12 Physics Chapter 7
NCERT MCQ Questions for Class 12 Physics Chapter 7 Alternating current. Alternating current MCQ Questions with Answers from Class 12 Physics.
Alternating current MCQ Questions Class 12 Physics Chapter 7
Alternating current Multiple Choice Questions with Answers Class 12 Physics Chapter 7 PDF is available.
1) The voltage which varies like a sine function with time is called as
a) DC voltage
b) AC voltage
c) Both a and b
d) None
Ans: b) AC voltage
2) The current driven by AC voltage is called as
a) DC current
b) Eddy current
c) AC current
d) None
Ans: c) AC current
3) The root mean square or effective current is given by
a) 0.707im
b) im/√2
c) 0.414im
d) Both a and b
Ans: d) both a and b
4) The phasors V and I for the resistance are in the same direction which means phase angle between the voltage and current is
a) Π
b) π/2
c) 0
d) None
Ans: c) 0
5) The quantity wL is analogous to resistance and it is called as
a) Capacitive reactance
b) Inductive reactance
c) Inductance
d) None
Ans: b) inductive reactance
6) The inductive reactance is given by
a) XL = w/L
b) XL= w/L2
c) XL= wL
d) XL= wL2
Ans: c) XL = wL
7) The SI unit of inductive reactance is
a) Ampere
b) Ohm
c) Volt
d) Henry
Ans: b) ohm
8) The inductive reactance is directly proportional to
a) Inductance L
b) Frequency of the current w
c) Both a and b
d) None
Ans: c) both a and b
9) The average power supplied to an inductor over one complete cycle is
a) Unity
b) Infinity
c) Constant
d) Zero
Ans: d) zero
10) 1/wC is called as
a) Inductive reactance
b) Capacitive reactance
c) Self inductance
d) Mutual inductance
Ans: b) capacitive reactance
11) The capacitive reactance is given by
a) Xc = wC
b) Xc= 1/wC
c) Xc= w/C
d) None
Ans: b) Xc= 1/wC
12) The SI unit of capacitive reactance is
a) Volt
b) Henry
c) Ohm
d) Ampere
Ans: c) ohm
13) The capacitive reactance is inversely proportional to
a) Frequency
b) Capacitance
c) Both a and b
d) None
Ans: c) both a and b
14) If the frequency is driven by an energy source at a frequency near the natural frequency then ____ takes place.
a) Mutual induction
b) Self induction
c) Resonance
d) None
Ans: c) resonance
15) In case of resonance the amplitude of oscillation is
a) Small
b) Medium
c) Large
d) Uniform
Ans: c) large
16) When Xc= XL then at that time frequency is called as
a) Natural frequency
b) System’s frequency
c) Resonant frequency
d) None
Ans: c) resonant frequency
17) At resonant frequency the impedance is
a) Maximum
b) Minimum
c) Both a and b
d) None
Ans: b) minimum
18) The resonant frequency is given by
a) 1/LC
b) 1/√LC
c) LC
d) None
Ans: b) 1/√LC
19) At resonant frequency current amplitude is
a) Minimum
b) Maximum
c) Both a and b
d) None
Ans: b) maximum
20) At resonant frequency
a) Impedance is minimum
b) Current amplitude is maximum
c) Both a and b
d) None
Ans: c) both a and b
21) WoL/R is called as
a) Resonant factor
b) Quality factor
c) Quantity factor
d) None
Ans: b) quality factor
- In case you have missed:- Previous Chapter MCQ Questions
22) The quantity Cosx is called as where X is the phase angle between voltage and current
a) Current factor
b) Voltage factor
c) Quality factor
d) Power factor
Ans: d) power factor
23) The circuit which contains only pure R is called as
a) Inductive circuit
b) LCR circuit
c) Resistive circuit
d) None
Ans: c) resistive circuit
24) For resistive circuit power factor is
a) 1
b) 0
c) -1
d) None
Ans: a) 1
25) The circuit which contains only an inductor is called as
a) Purely inductive
b) Resistive
c) Capacitive
d) LCR
Ans: a) purely inductive
26) The circuit which contains only capacitor is called as
a) Purely inductive
b) Purely capacitive
c) Purely resistive
d) None
Ans: b) purely capacitive
27) The power dissipation in purely resistive circuit is
a) Minimum
b) Zero
c) Maximum
d) Constant
Ans: c) maximum
28) The power factor for purely inductive or purely capacitive circuit is
a) 1
b) -1
c) Zero
d) Infinity
Ans: c) zero
29) In purely inductive or purely capacitive circuit the power dissipation is
a) Maximum
b) Minimum
c) Zero
d) No power dissipation
Ans: d) no power dissipation
30) The power dissipated at resonance in series LCR circuit is
a) Minimum
b) Maximum
c) Zero
d) None
Ans: b) maximum
31) The total energy of LC circuit is given by
a) q2C/2
b) q2/2C
c) 1/q2C
d) None
Ans: b) q2/2C
32) The transformer works on the principle of
a) Self induction
b) Mutual induction
c) Both a and b
d) None
Ans: b) mutual induction
33) In case of transformer the power input is equal to power output when
a) No energy losses
b) Transformer is 100% efficient
c) Both a and b
d) None
Ans: c) both a and b
34) If the secondary coil has less turns than primary then that transformer is called as
a) Step down transformer
b) Step up transformer
c) Both a and b
d) None
Ans: a) step down transformer
35) In step down transformer voltage is
a) Stepped down
b) Reduced
c) Increased
d) Both a and b
Ans: c) both a and b
36) In step down transformer the current is
a) Reduced
b) Increased
c) Remains same
d) None
Ans: b) increased
37) If the secondary coil has greater number of turns than the primary then that transformer is called as
a) Step down transformer
b) Step up transformer
c) Both a and b
d) None
Ans: b) step up transformer
38) In step up transformer, the voltage is
a) Stepped up
b) Reduced
c) Increased
d) Both a and c
Ans: d) both a and c
39) In step up transformer the current is
a) Increased
b) Decreased
c) Stepped up
d) None
Ans: b) decreased
40) Which of the following reasons for small energy losses in actual transformers
a) Flux leakage
b) Resistance of the windings
c) Hysterisis
d) All
Ans: d) all
41) Resonant frequency is measured in
a) Henry
b) Hertz
c) Volt
d) Meter
Ans: b) Hertz
42) The power rating of an element uses in an AC circuit refers to its
a) Power rating
b) Current power rating
c) Voltage power rating
d) Both b and c
Ans: c) voltage power rating
43) The device used to low voltage into high voltage and vice versa is called as
a) Voltmeter
b) Transistor
c) Transformer
d) Potentiometer
Ans: c) transformer
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