Question

The capacity and the energy stored in a parallel plate condenser with air between its plates are respectively $C_{0}and{W}_0$.If the air is replaced by the glass (dielectric constant =$5$) between the plates, the capacity of the plates and the energy stored in it will respectively be:

• A. $5C_{0}and5W_0$
• B. $5C_{0}and{W}_0/5$
• C. $C_0/5and5W_0$
• D. $C_0/5and{W}_0/5$

Answer 1

The correct option is B $5C_{0}and{W}_0/5$

When a dielectric K is introduced in a parallel plate capacitor its capacity becomes k times

Hence $C=5C_0$

Energy shared$=W_0=\frac{q^0}{2C_0}$

$\therefore W=\frac{q^0}{2C^1}=\frac{q^2}{2\times 5C_0}\Rightarrow W^1=\frac{W_0}{5}$