The electric field at a distance of 0.4m from a point charge q is 20.0N/C. Find the charge “q”.

Help it seems simple but I keep getting a huge number

To find the charge q, you can use Coulomb's law, which states that the electric field (E) created by a point charge is directly proportional to the charge (q) and inversely proportional to the square of the distance (r) between the charge and the point where the electric field is measured.

The formula for Coulomb's law is:

E = k * (q / r^2)

where E is the electric field, q is the charge, r is the distance, and k is the electrostatic constant (k ≈ 8.99 * 10^9 N m^2/C^2).

In this case, you are given the electric field (E = 20.0 N/C) and the distance (r = 0.4 m). Let's substitute these values into the formula and solve for q:

20.0 N/C = (8.99 * 10^9 N m^2/C^2) * (q / (0.4 m)^2)

Simplifying the equation:

20.0 N/C = (8.99 * 10^9 N m^2/C^2) * (q / 0.16 m^2)

Now, cross multiply to solve for q:

20.0 N/C * 0.16 m^2 = (8.99 * 10^9 N m^2/C^2) * q

3.2 N m = (8.99 * 10^9 N m^2/C^2) * q

Now, isolate q by dividing both sides of the equation by (8.99 * 10^9 N m^2/C^2):

q = (3.2 N m) / (8.99 * 10^9 N m^2/C^2)

Calculating q:

q ≈ 3.56 * 10^-10 C

Therefore, the charge q is approximately 3.56 * 10^-10 Coulombs.