Q.

The circuit shown in the figure contains an inductor L, a capacitor C0, a resistor R0 and an ideal battery. The circuit also contains two keys K1 and K2. Initially, both the keys are open and there is no charge on the capacitor. At an instant, key K1 is closed and immediately after this the current in R0 is found to be I1. After a long time, the current attains a steady state value I2. Thereafter, K2 is closed and simultaneously K1 is opened and the voltage across C0 oscillates with an amplitude V0 and angular frequency ω0.

Match the quantities mentioned in List-I with their values in List-II and choose the correct option.                    [2024]

  List-I   List-II
(P) The value of I1 in Ampere is (1) 0
(Q) The value of I2 in Ampere is (2) 2
(R) The value of ω0 in kilo-radians/s is (3) 4
(S) The value of V0 in Volt is (4) 20
    (5) 200

 

1 P → 1; Q → 3; R → 2; S → 5  
2 P → 1; Q → 2; R → 3; S → 5  
3 P → 1; Q → 3; R → 2; S → 4  
4 P → 2; Q → 5; R → 3; S → 4  

Ans.

(1)

(P)  When key K1 is closed, current in R0 is I1

At t=0, the circuit is as follows.

I1=0

(Q)  After a long time, the inductor behaves as a wire, so

I2=VR=205=4 A

(R)  When K2 is closed and K1 is open,

ω0=1LC=125×10-3×10×10-6=15×10-4

∴  ω0=2×103 rad/s    ∴  ω0=2 kilo-radian/s

(S)  When K2 is closed and K1 is open,

12LI22=12CV02

12(25×10-3)(4)2=12(10×10-6)V02

V02=2500×16  or,  V0=50×4=200 V