Q. A parallel plate condenser with oil (dielectric constant 2) between the plates has capacitance$\ C$. If oil is removed, the capacitance of capacitor becomes
A) $\sqrt{2C}$
B) $2C$
C) $\frac{C}{\sqrt{2}}$
D) $\frac{C}{2}$
Explanation
(d) The capacitance of a parallel plate capacitor with dielectric (oil) between its plates is
$C = \frac{K\varepsilon_{0}A}{d}$ …(i)
where symbols have their usual meanings. when dielectric (oil) is removed, so capacitance
$C = \frac{\varepsilon_{0}A}{d}$ …(ii)
Comparing Eqs. (i) and (ii), we get
$C = KC_{0}$
$\Rightarrow C_{0} = \frac{C}{K} = \frac{C}{2}\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ (\therefore K = 2)\ $
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.