A particle of mass 1 mg loses 108 electrons and then stays in equilibrium against gravity inside electric field. What should be the magnitude and direction of the electric field intensity?

Explanation

To solve the problem, we need to find the magnitude and direction of the electric field intensity that allows a particle of mass 1 mg to remain in equilibrium against gravity after losing 10^8 electrons.

### Step-by-step Solution:

1. **Identify the mass of the particle**:
The mass of the particle is given as 1 mg. We convert this to kilograms:
\[
m = 1 \text{ mg} = 1 \times 10^{-3} \text{ g} = 1 \times 10^{-6} \text{ kg}
...