<h2>
Answer:</h2>
(a) +2 x 10² N/C (upwards)
(b) -2.2μN or -2.2 x 10⁻⁶N (downwards)
<h2>
Explanation:</h2>
The force (F) acting on a particle of charge (Q) at a particular point is related to its electric field (E) by the following;
F = Q x E ----------------------(i)
This means that the force acting on the charged particle is the product of its charge and the electric field at that point.
<em>(a) Given</em>;
Q = charge of the particle = 2.3 x 10⁻⁸ C
F = force acting on the particle = 4.6 x 10⁻⁶N
<em>Substitute these values into equation (i) as follows;</em>
=> 4.6 x 10⁻⁶ = 2.3 x 10⁻⁸ x E
=> E = 4.6 x 10⁻⁶ ÷ 2.3 x 10⁻⁸
=> E = 2 x 10² N/C
Since the value is positive, the electric field is directed upwards.
Therefore, the electric field at that point is +2 x 10² N/C
<em>(b) If a charge of q = -1.1 x 10⁻⁸ is placed there, the force (F) acting is calculated as follows;</em>
<em>Substitute Q = q into equation (i) as follows;</em>
F = q x E
<em>Substitute the value of q and E = 2 x 10² N/C into the equation above as follows;</em>
F = -1.1 x 10⁻⁸ x 2 x 10²
F = -2.2 x 10⁻⁶ N
F = -2.2μN
Since the value of the force, F, is negative, it means it is directed downwards.
Therefore the force on the charge is -2.2μN
