Question

An isolated parallel plate capacitor is maintained at a certain potential difference. When a 3 mm thick slab is introduced between the plates, in order to maintain the same potential difference the distance between the plates is increased by 2.4 mm. The dielectric constant of the slab will be ______.

Options

• 1.00

• 2.00

• 4.00

• 5.00

Answer 1

An isolated parallel plate capacitor is maintained at a certain potential difference. When a 3 mm thick slab is introduced between the plates, in order to maintain the same potential difference the distance between the plates is increased by 2.4 mm. The dielectric constant of the slab will be 5.00.

Explanation:

q = q',

`C_0V_0 = CV, C_0 = C`

as V = V₀ given

`C_0 = (∈_0A)/d`,

`C_1 = (∈_0A)/(d - t + t/K)`

But by increasing d to d + 0.24 cm then

C₁ becomes C = `(∈_0A)/((d + 0.24 - t) + t/K)`

d = `d + 0.24 - t + t/k,`

K = `t/(t - 0.24) = 5`