Two idential point charges Q are kept at a distance r from each other. A third point charge is placed on the line joing the above two charges such that all the three charges are in equilibrium. The third charge
(a) should be of magnitude q=………..
(b) should be of sign .......
(c ) should be placed ........ .

Explanation

To solve the problem step by step, we need to analyze the forces acting on the third charge when it is placed between the two identical point charges.

### Step-by-Step Solution:

1. **Understanding the Setup:**
- We have two identical point charges, both with charge \( Q \), placed at a distance \( r \) apart.
- We need to place a third charge \( q \) on the line joining the two charges such that the system is in equilibrium.

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