Assertion:  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

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  $\frac{\mathrm{\pi }}{2}$. Then it is a/an

• resistor circuit

• capacitor

• inductor circuit

• CR circuit

168.

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