In the circuit shown in fig. when the switch is closed, the capacitor charges with a time constant

Options

A. RC
B. 2 RC
C. `(1)/(2)RC`
D. RC log2

Answer

A

Explanation

In the steady state, no
current is flowing through
the capactior branch, so the
capacitor branches may be
removed from the circuit, the equivalent circuit is shown in
`:. R_(AB) = R_1 +R_2 = r +r = 2r`