Two point charges and are placed apart in air

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

Problem

Two point charges

+4\,\mu\text{C}

and

-2\,\mu\text{C}

are placed

20\,\text{cm}

apart in air. Calculate the magnitude of the force between them. (a)

1.8\,\text{N}

(b)

0.36\,\text{N}

(c)

7.2\,\text{N}

(d)

0.18\,\text{N}