Question

Two identical charged spheres are suspended by strings of equal lengths. The strings make an angle of 30° with each other. When suspended in a liquid of density 0.8 g cm^–3, the angle remains the same. If density of the material of the sphere is 16 g cm^–3, the dielectric constant of the liquid is

(1) 4

(2) 3

(3) 2

(4) 1

Answer 1

3 

From F.B.D of sphere, using Lami’s theorem