Question

Dielectric slab of area A passes between the capacitor plates of area 2A with a constant speed v. The variation of current (i) through the circuit as function of time (t) can be qualitatively represented as (the length of dielectric slab is half the length of the capacitor plates)

• A.
• B.
• C.
• D.

Answer 1

The correct option is B

$(\frac{{ϵ}_{0}klx}{d}+\frac{{ϵ}_0(2A-lx)}{d})V=Q;i=V(\frac{{ϵ}_{0}kl}{d}+\frac{-{ϵ}_{0}l}{d})\frac{dx}{dt}=$ constant; as the dielectric leaves $c\downarrow \Rightarrow Q\downarrow \Rightarrow i$ is -ve.