A 15 C point charge is located on the yaxis at (0, 0.25). A second charge of 10 C is located on the x-axis at (0.25, 0). If the two charges are separated by air, what is most nearly the force between them?

10.8 N

Explanation:

The question requires the force between them, hence, we only need the magnitude of the force without considering what direction it's acting.

Parameters given:

Q1 = 15 * 10^(-6) C

Q2 = 10 * 10^(-6) C

The diagram explains better.

The electrostatic force BETWEEN Q1 and Q2 is:

F = (k * Q1 * Q2)/r²

Using Pythagoras theorem:

r² = 0.25² + 0.25² = 0.0625 + 0.0625

r² = 0.125

=> F = [9 * 10^9 * 15 * 10^(-6) * 10 * 10^(-6)]/0.125

F = 1.35/0.125

F = 10.8 N

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