A point charge is kept at the origin of a Cartesian coordinate system

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

Problem

A point charge

+2.0\,\mu\text{C}

is kept at the origin of a Cartesian coordinate system. An external uniform electric field of magnitude

5.0\times10^{4}\,\text{N C}^{-1}

acts along the positive

x

–axis. (a) Obtain an expression for the net electric field

E_{\text{net}}(x)

at any point on the

x

–axis in terms of the distance

x

from the origin. (b) Hence calculate the coordinate

x

(with sign) at which the net electric field on the

x

–axis becomes zero. (c) Find the magnitude and direction of the net electric field at the point whose coordinate is

x = 0.15\,\text{m}