A point charge of is fixed in vacuum

PHYSICS · Multi-part · A Level · Physics · Fields and their consequences · Fields and their consequences

Problem

A point charge of

+2\,\mu\text{C}

is fixed in vacuum. Point

P

is located

0.50\,\text{m}

from this charge. Answer the following questions: (i) Calculate the electric potential at point

P

. (ii) Determine the work that must be done by an external agent to bring a test charge of

+3\,\text{nC}

from infinity to point

P

without acceleration. (iii) If the test charge in part (ii) is replaced by

-3\,\text{nC}

, what is the change (magnitude and sign) in the potential energy of the system? Explain the reason for the sign.