Question

A sphere of radius 1cm has potential of 8000 v, then energy density near its surface will be ...... 

(A) 64 × 10⁵(J/m³) 

(B) 2.83(J/m³) 

(C) 8 × 10³(J/m³) 

(D) 32(J/m³)

Answer 1

The correct option (B) 2.83 (J/m³)

Explanation:

Energy density = (1/2)∈₀E²

= (1/2) × 8.86 × 10^–12 × (v/r)²

= 4.43 × 10^–12 × [(8000)/(10^–2)]²

= 283.5 × 10^–2

= 2.83 J/m³