Q. An air filled parallel plate capacitor the capacity $C.$ If distance between plates is doubled and it is immersed in a liquid then capacity becomes twice. Dielectric constant of the liquid is
A) 1
B) 2
C) 3
D) 4
Explanation
(d) $C = \frac{\varepsilon_{0}A}{d}$ …(i)
$C^{'} = \frac{\varepsilon_{0}KA}{2d}$ …(ii)
From equation (i) and (ii)
$\frac{C^{'}}{C} = \frac{K}{2} \Rightarrow 2 = \frac{K}{2} \Rightarrow K = 4$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.