Question

Q:-6 The value of charge q at the centre of two equal and like charges Q so
that three are in equilibrium is-
a) Q b) +Q/4 c)-Q/4
d) 0/2
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Answer 1

Answer:

Your Ans.

(C) - Q/4.

Hope this Helpful.

Answer 2

Given:

Two like charges Q

Another charger q

To find:

The value of charge q at the centre of two equal and like charges Q so

that three are in equilibrium is

Solution:

Let two equal charges Q each placed at points A and B at a distance r apart. C is the centre of AB where charge q is placed.

• For equilibrium, net force on charge Q = 0

         ∴ $\frac{kQq}{(r/2)^2}$ + $\frac{kQQ}{r^2}$ = 0

         ⇒$\frac{4kQq}{r^2}$ = - $\frac{kQQ}{r^}$

              q = -Q/4

The value of charge q at the centre of two equal and like charges Q so

that three are in equilibrium is -Q/4