Two identical point charges of are fixed in air on the -axis at and

PHYSICS · Subjective · CBSE · Physics · Electrostatic Potential and Capacitance · Electrostatic Potential and Capacitance

Problem

Two identical point charges of

+4\,\mu\text{C}

are fixed in air on the

x

-axis at

x=-0.20\,\text{m}

and

x=+0.20\,\text{m}

. An unknown point charge

q

is placed at the origin. The electric potential at point

P(0,\,0.20\,\text{m})

is found to be zero. Determine the magnitude and sign of

q

. Take

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