Question

At time $t=0$, a battery of $10V$ is connected across points A and B in the given circuit. If the capacitors have no charge initially, at what time (in seconds) does the voltage across them becomes $4$ volt?
(take $\ln 5=1.6,\ln 3=1.1$)

Answer 1

$V=V_0[1-e^{-t/RC}]\Rightarrow 4=10[1-e^{1/4}]\Rightarrow e^{\frac{1}{4}}=\frac{5}{3}\Rightarrow \frac{t}{4}=\ln \frac{5}{3}$

$t=4[\ln 5-\ln 3]=2sec$