Capacitance of a capacitor becomes $\frac{4}{3}$ times its original value if a dielectric slab of thickness…

Capacitance of a capacitor becomes $\frac{4}{3}$ times its original value if a dielectric slab of thickness $t=d / 2$ is inserted between the plates $(d=$ separation between the plates). The dielectric constant of the slab is
  1. 2
  2. 4
  3. 6
  4. 8

Solution

$C=\frac{\varepsilon_{0} A}{d}, \quad \frac{4 C}{3}=\frac{\varepsilon_{0} A}{\left[d-\frac{d}{2}+\frac{d}{2 k}\right]}, \frac{4}{3}=\frac{d}{\frac{d}{2}+\frac{d}{2 k}}, 2 d+\frac{2 d}{k}=3 d, \quad k=2$ .

Asked in: JEE Mains - Capacitance - Test 2

Practice more Electrostatics questions on Aicharya