Question

If a small sphere of mass m and charge q is hung from a silk thread at an angle of theta with the surface of the vertical charged conducting plate then the equilibrium of the sphere the surface charge density of the plate will be

Answer 1

Answer:

The surface charge density of the plate will be mg ∈° tan  Ф / q

Explanation:

The two components of tension are,

T cos Ф = mg

T sin Ф  = Electric force

T sin Ф = qE

where E represents Electric field due to the plate.

Tan Ф = qE / mg

E = mg tan  Ф / q

σ / ∈° = mg tan  Ф / q

σ = mg ∈° tan  Ф / q