Question

Three charges each of +q, are placed at the vertices of an equilateral triangle. The charge needed at the centre of the triangle for the charges to be in equilibrium is –

• A. $\frac{- q}{\sqrt{3}}$
• B. –$\sqrt{3}q$
• C. $\sqrt{3}q$
• D. –

Answer 1

Answer: (A)

$\frac{- q}{\sqrt{3}}$

Answer 2

F =

= $\sqrt { 1 + 1 + 1 }$ =

F_center =

F + F_center = 0

= + = 0

= = –

\ Q = – $\frac { \mathrm { q } } { \sqrt { 3 } }$ = –