Question

Consider a system of three charges q/3, q/3 and – 2q/3 placed at points A, B and C respectively as shown in the figure. It the radius of the circle is R and ∠CAB = 60° then the electric field at centre 0 is ……. 

(A) [q/(8π∈₀R²)] 

(B) [q²/(54π∈₀R²)] 

(C) [q/(6π∈₀R²)] 

(D) 0

Answer 1

The correct option (C) [q / (6π∈₀R²)]  

Explanation:

Net electric field due to both charges (q/3) will get cancelled.

∴ electric field of O is due charge (2q/3) & is

E = [{k (2q/3)}/R²] -------- as E ∙ (kQ/r²)

= (2q/3) × [1/(4π∈₀)] × (1/R²)

= [q/(6π∈₀R²)]