The force between two point electric charges kept at a distance d apart in air is F. If these charges are kept at the sme distance in water, the force between the charges is F'. The ratio `F'//F` is equal to ……….. .

Explanation

To solve the problem, we need to find the ratio \( \frac{F'}{F} \) where \( F \) is the force between two point charges in air and \( F' \) is the force between the same charges in water.

### Step-by-Step Solution:

1. **Understanding the Force Between Charges**:
The force \( F \) between two point charges \( q_1 \) and \( q_2 \) separated by a distance \( d \) in a medium is given by Coulomb's Law:
\[
F = \frac{1}{4 \pi \epsilon} \frac{q_1 q_2}{d^2}
...