Two identical point charges are initially apart

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

Problem

Two identical point charges

q=3.0\,\mu\text{C}

are initially

0.30\,\text{m}

apart. They are then slowly moved until their separation is

0.60\,\text{m}

. What is the work done by the external agent during this process? (Take

k=8.99\times10^{9}\,\text{N\,m}^2\!\,/\!\,\text{C}^2

.) (a)

+0.270\,\text{J}

(b)

+0.135\,\text{J}

(c)

-0.135\,\text{J}

(d)

-0.067\,\text{J}