A capacitor of capacitance 100 μ F is connected across a battery of emf 6.0 V through a resistance of 20 k Ω for 4.0 s. The battery is then replaced by a thick wire. What will be the charge on the capacitor 4.0 s after the battery is disconnected ?
c=100μF,Eμf=6V,
r=20K,T=4s
Charging,
Q=CV(1−e−tRC)
=6×10−4(1−e−2)
=5.187×10−4C
Discharging
Q=q(e−tRC)
=5.184×10−4×e−2
=0.7×10−4C=70μC