Multiple Choice QuestionsAssertion: No power loss associated with pure capacitor in ac circuit.
Reason: No current is flowing in this circuit.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
A 50 Hz a.c source of 20 volts is connected across R and C as shown in figure. The volage across R is 12 volt. The voltage across C is
8 V
16 V
10 V
not possible to determine unless values of R and C are given
The circuit shown in the figure acts as
tuned filter
low pass filter
high pass filter
rectifier
If an ideal parallel LC circuit, the capacitor is changed by connecting it to a d.c source which is then disconnected. The current in the circuit
becomes zero instantaneously
grows monotonically
decays monotonically
oscillates instantaneously
D.
oscillates instantaneously
When the capacitor is connected to a d.c source and then disconnected, it gets charged then it starts discharging through the inductor. An induced emf id produced in the circuit which opposes the growth of the current in L. When the capacitor is fully discharged, the electric he electric energy stored in the capacitor. 
gets converted fully into magnetic field energy 
. As soon as the discharge of the capacitor is complete, current stops and the magnetic flux linked with L starts collapsing. Therefore, an induced emf is again developed which starts recharging the capacitor in the opposite direction. When the recharging is completed, all magnetic energy stored in L appears as the electric energy between the plates of the capacitor. The entire process keeps on repeating and the energy taken from the cell keeps on oscillating between C and L. Hence the current in the circuit starts oscillating as soon as the d.c. source charging the capacitor is disconnected.
A capacitor of capacitance 2μF is connected in the tank circuit of an oscillator oscillating with a frequency of 1 kHz. If the current flowing in the circuit is 2 mA, the voltage across the capacitor will be
0.16 V
0.32 V
79.5 V
159 V
Assertion: The quantity L/R possesses dimension of time.
Reason: To reduce the rate of increase of current through a solenoid, we should increase the time constant ( L/R ).
If both the assertion and reason are true and reason is a correct explanation of assertion
If both assertion and reason are true but assertion is not correct explanation of the assertion
If the assertion is true but the reason is false.
If both assertion and reason are false.
If in a circuit current lags behind EMF by . Then it is a/an
resistor circuit
capacitor
inductor circuit
CR circuit
The inductance of a coil in which a current of 0.2 A is increasing at the rate of 0.5 A/s represents a power flow of 0.5 W, is
2 H
5 H
10 H
20 H
In a LCR series circuit, the potential difference between the terminals of the inductance is 60 V, between the terminals of the capacitor, is 30 V and that across the resistance is 40 V. Then, the supply voltage will be equal to
50 V
70 V
130 V
10 V
A choke is preferred to resistance for limiting current in AC circuit because
choke is cheap
there is no wastage of power
choke is compact in size
choke is a good absorber of heat
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