Three point charges lie on the –axis

PHYSICS · Multi-part · CBSE · Physics · Electrostatic Potential and Capacitance · Electrostatic Potential and Capacitance

Problem

Three point charges lie on the

y

–axis. Charge

q_{1}=+5.0\,\mu\text{C}

is at

y=0

, charge

q_{2}=+5.0\,\mu\text{C}

is at

y=0.20\,\text{m}

, and charge

q_{3}=-5.0\,\mu\text{C}

is at

y=0.40\,\text{m}

. The charge

q_{3}

is then moved to a new position at

y=0.10\,\text{m}

while the other two charges remain fixed. (a) Compute the total electric potential energy of the three–charge system before

q_{3}

is moved. (b) Compute the total electric potential energy after

q_{3}

is relocated. (c) Determine the external work required to move

q_{3}

from

y=0.40\,\text{m}

y=0.10\,\text{m}

. State clearly whether this work is positive, negative, or zero and interpret its physical meaning.