Question

Electric charges of + 10μc, 5μc, – 3μc and 8μc are placed at the corners of a square of side √2m the potential at the centre of the square is……. 

(A) 1.8 V 

(B) 1.8 × 10⁵V 

(C) 1.8 × 10⁶V 

(D) 1.8 × 10⁴V

Answer 1

The correct option (B) 1.8 × 10⁵V

Explanation:

side of square = √2m

∴ diagonal = 2cm

∴ r = [(diagonal)/2] = 1m

∴ Potential at centre 'o' = (k/r) (Q₁ + Q₂ + Q₃ + Q₄)

∴ V = [(9 × 10⁹)/1] [10 ×10^–6 + 5 × 10^–6 – 3 ×10^–6 + 8 × 10^–6]

= 9 × 10⁹ [20 × 10^–6]

= 180 × 10³

∴ V = 1.8 ×10⁵ V