12th Class Physics MCQS
The AC system is preferred to DC system because:
DC motor angular velocity is affected badly
High voltage AC transmission is less efficient
AC voltage can be easily changed in magnitude
Domestic appliance require AC voltage for their operation
The peak to peak value of alternating voltage is
Vo
None of these
2Vo
The resonance frequency is given by:
f1 = 1/ 2?C?L
fr = 2??LC
fr = 1/2?LC
fr = 1/ 2??LC
Radio frequency choke is
Iron cored
None of these
Air as well as iron cored
Air Cored
Power dissipation in A.C circuit is expressed as:
IrmsxVrmsCos?
IxVCos?
P =Irms x Vrms Sin?
Irms x Vrms Sin2?
The internal resistance of a capacitor is called:
Resistance
Conductance
Reactance
Impedance
A capacitor is perfectly insulator for:
Direct as well as alternating current
Direct current
None of these
Alternating current
XL=
2?fL
fL/2?
1/2?fL
2?fL
In frequency modulation, the amplitude of carrier waves is
Remains constant
Decreases
Increases
None of these
At high frequency, the current through a capacitor is
Infinity
Small
Large
Zero
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