What should be the charge on a sphere of radius 4 cm, so that when it is brought in contact with another sphere of radius 2 cm carrying charge of 10 `mu C`, there is no transfer of charge from one sphere to other ?

Explanation

To solve the problem, we need to determine the charge \( Q \) on a sphere of radius 4 cm such that when it is brought into contact with another sphere of radius 2 cm carrying a charge of \( 10 \, \mu C \), there is no transfer of charge between the two spheres. This occurs when the electric potentials of both spheres are equal.

### Step-by-Step Solution:

1. **Understand the Concept of Electric Potential**:
The electric potential \( V \) at the surface of a charged sphere is given by the formula:
\[
V = \frac{kQ}{R}
...