For the arrangement shown in the switch is closed at t =0. The time after which the current becomes `2.5muAS` is given by (take in 2 =0.69)

Options

A. 10 S
B. 5 S
C. 7 S
D. 0.693 S

Answer

C

Explanation

In the steady-state conducting,
no current will flow through the
capacitor C.
Current in the outer circuit
`I = (2V - V)/(2R + R) = (V)/(3R)`
Potential difference between A and B is
`V_A - V +V +IR = V_B or V_B - V_A = IR = ((V)/(3R))R =(V)/(3)`