The field strength of a point charge at a distance of 0.2 m from it is 225 V / m. Determine the charge modulus.

The field strength of a point charge is determined by the formula:

E = k * q / r ^ 2

Where,

k = 9 * 10 ^ 9 (n * m2 / Cl2) – constant; q is the electric charge that creates an electric field; r is the distance from the charge to the place where the electric field strength is determined.

From the above formula, we determine the value of the electric charge:

q = E * ^ r2 / k.

Let’s substitute numerical values in the last formula:

q = E * r ^ 2 / k = 225 * 0.2 / 9 * 10 ^ 9 = 5625/9 * 10 ^ 9 = 625 * 10 ^ -9 (Cl).

Answer: | q | = 625 * 10 ^ -9 (Cl).