Question 2.53: A capacitor of value 1 μF and a resistor of 5.45 MΩ are conn......

Time constant,             \tau=R C=5.45 \times 10^6 \times 1 \times 10^{-6} \mathrm{sec}

= 5 45. seconds

or,                        e^{-t / 5.45}=1-0.6=0.4

or,                       e^{-t / 5.45}=\frac{1}{0.4}=2.5

or,                        \frac{t}{5.45}=\ln 2.5=0.915

or,                        t=0.915 \times 5.45=4.98 \text { seconds }