Which one of the following expressions represents the electrostatic force on charge…

PHYSICS · Single correct · A Level · Physics · Fields and their consequences · Fields and their consequences

Problem

Which one of the following expressions represents the electrostatic force on charge

q_2

due to charge

q_1

separated by a distance

r

in vacuum? (a)

k\dfrac{q_1q_2}{r}\,\hat{\mathbf r}_{12}

(b)

k\dfrac{q_1q_2}{r^{2}}\,\hat{\mathbf r}_{21}

(c)

k\dfrac{q_1q_2}{r^{2}}\,\hat{\mathbf r}_{12}

(d)

k\dfrac{|q_1q_2|}{r^{2}}\,\hat{\mathbf r}_{12}