Question 938: Electrostats & Capacitance

Question

Four point charges $$-$$Q, $$-$$q, 2q and 2Q are placed, one at each corner of the square. The relation between Q and q for which the potential at the centre of the square is zero is

Accepted Answer

Let the side length of square be 'a' then potential at centre O is
$$V = {{k( - Q)} \over {{a \over {\sqrt 2 }}}} + {{k( - q)} \over {{a \over {\sqrt 2 }}}} + {{k(2q)} \over {{a \over {\sqrt 2 }}}} + {{k(2Q)} \over {{a \over {\sqrt 2 }}}} = 0$$
= Ã¢ÂÂ Q Ã¢ÂÂ q + 2q + 2Q = 0 = Q + q = 0
$$ 	herefore $$ Q = Ã¢ÂÂ q

Answer

Q = $$-$$q

Answer

Q = $$ - {1 \over q}$$

Answer

Q = q

Answer

Q = $${1 \over q}$$

Electrostats & Capacitance

Four point charges $-Q, -$q, 2q and 2Q are placed, one at each corner of the square. The relation between Q and q for which the potential at the centre of the square is zero is

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