Question

If the distance between the plates of parallel plate capacitor is halved and the dielectric constant of dielectric is doubled, then it's capacity will ______

Options

• increase by 16 times.

• increase by 4 times.

• increase by 2 times.

• remain the same.

Answer 1

If the distance between the plates of the parallel plate capacitor is halved and the dielectric constant of dielectric is doubled, then its capacity will increase by 4 times.

Explanation:

C = `("k"epsilon_0"A")/"d" ∝ "k"/"d"`

Hence,  `"C"_1/"C"_2 = "k"_1/"k"_2 xx "d"_2/"d"_1 = "k"/(2"k") xx ("d""/"2)/"d" =  1/4`

Therefore, C₂ = 4C₁

OR

`"I"/2  "C"  ("V"_2^2 - "V"_1^2)`

Hence, `1/2 xx 15 xx 10^-6 xx (25^2 - 15^2)`

Therefore, `"C"_2 = 4"C"_1`