Two point charges and are apart in vacuum and repel each other with a force

PHYSICS · Subjective · A Level · Physics · Fields and their consequences · Fields and their consequences

Problem

Two point charges

+q

and

+4q

are

20\,\text{cm}

apart in vacuum and repel each other with a force

F

. They are now placed

40\,\text{cm}

apart in kerosene whose relative permittivity is

k=2.0

. Calculate the new force and express it as a fraction of

F