Two identical capacitors A and B , charged to the same potential 5 V are connected in two different circuits as shown below at time t = 0 . If the charge on capacitors A and B at time t = C R is Q A a

Question

Two identical capacitors A and B , charged to the same potential 5 V are connected in two different circuits as shown below at time t = 0 . If the charge on capacitors A and B at time t = C R is Q A and Q B respectively, then (Here e is the base of natural logarithm)

TestHub · Accepted Answer

Charge on capacitor after charging with a battery of potential $V$ , $Q = C V$

Now, capacitor $A$ is connected as shown in the figure.

As diode is in reverse bias, so capacitor charge remains same after time $t = C R$ .

$∴ Q_{A} = C V$

In case $B$ , capacitor is connected as shown in the figure.

Here, diode is in forward bias, so capacitor discharges and its charge decays as

$Q_{B} = Q \cdot e^{\frac{- t}{R C}}$

where, $t = R C$

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