Question

Three concentric metallic spherical shell A, B and C or radii a, b and c (a<b<c) have surface charge densities - σ, + σ, and - σ respectively. The potential of shell A is : 

(A) ( σ/ε₀ ) [a+b-c] 

(B) ( σ/ε₀ ) [a-b+c] 

(C) ( σ/ε₀ ) [b-a-c] 

(D) None 

Answer 1

Correct option (C) ( σ/ε₀ ) [b-a-c] 

Explanation: 

Potential at a due to charge of a = - 0 (σ/ ∈)

Potential at b due to charge of b = 0 ( σ/ ∈₀) (a)

(b) Potential at C due to charge of c =-( σ/ ∈₀) (b)