Question

A capacitor of capacitance $5\, \mu F$ is connected as shown in the figure. The internal resistance of the cell is $0.5\, \Omega .$ The amount of charge on the capacitor plate is

• A. $10\, \mu C$
• B. $5\, \mu C$
• C. $6\, \mu C$
• D. $10.2\, \mu C$

Answer 1

Answer: (A)

We know that capacitor offers infinite resistance for DC source.
Current taken from the cell
$i=\frac{E}{R +r}$
$\therefore i=\frac{2.5}{1+1+0.5}=1\, A$
Potential drop across capacitor
$V =E-i r$
$=2.5-1 \times 0.5=2\, V$
The current in $2\, \Omega$ resistor is zero.
Charge on capacitor
$Q=CV$
$=5 \times 2=10\, \mu C$