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Question
Two identical point charges, q each, are kept 2m apart in the air. A third point charge Q of unknown magnitude and sign is placed on the line joining the charges such that the system remains in equilibrium. Find the position and nature of Q.
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Solution
`(K(q)(Q))/x = (-K(q)(q))/2`
⇒ Q = `(-qx)/2`
∵ `(KqQ)/x = (KQq)/y`
x = y
x + y = 2
∴ x = y = 1
Q = `(-q)/2`
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