A particle having a charge of `2.0xx10^(-4) C` is placed directly below and at a separtion of 10 cm from the bob of a simple pendulum at rest. The mass of the bob is 100g. What charge should the bob be given so that the string becomes loose?

Explanation

To solve the problem, we need to determine the charge that should be given to the pendulum bob so that the tension in the string becomes zero, which implies that the bob is in a state of equilibrium due to the electric force acting on it.

### Step 1: Understand the Forces Acting on the Bob
The forces acting on the bob are:
1. The gravitational force (weight) acting downwards, \( F_g = mg \).
2. The electric force due to the charge below it, \( F_e \), which will act upwards if the charges are of the same sign (repulsive force).

### Step 2: Calculate the Gravitational Force
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