Two point charges are fixed in vacuum: (+3 , C ) at the origin and (-1 , C ) at ((0.40

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

Problem

Two point charges are fixed in vacuum:

+3\,\mu\text{C}

at the origin and

-1\,\mu\text{C}

(0.40\,\text{m},\,0)

. Find the magnitude of the electrostatic force on a

+2\,\mu\text{C}

test charge placed at the point

(0,\,0.30\,\text{m})

. Take

k = 9\times10^{9}\,\text{N m}^{2}\text{C}^{-2}

. (a)

0.67\,\text{N}

(b)

0.15\,\text{N}

(c)

0.56\,\text{N}

(d)

0.53\,\text{N}