Answer:
[tex]E=\frac{1}{4\pi.\epsilon_o} \times \frac{Q}{ d^2}[/tex]
Explanation:
In the given question we have a test charge q at a distance of d from form another charge Q which creates the field.
The electric field strength is force force per unit test charge, according to the Coulomb's law the force between two charges is given as:
[tex]F=\frac{1}{4\pi.\epsilon_0} \times \frac{Q.q}{d^2}[/tex]
where:
[tex]\epsilon_0=[/tex] permittivity of free space
Therefore,
[tex]E=\frac{F}{q}[/tex]
[tex]E=\frac{1}{4\pi.\epsilon_o} \times \frac{Q}{ d^2}[/tex]
