Two fixed charges (at ) and (at ) lie on the x-axis

PHYSICS · Subjective · AP · Physics C: Electricity and Magnetism · Electric Potential · Electric Potential

Problem

Two fixed charges

q_1 = +6.0\,\mu\text{C}

(at

x = 0

) and

q_2 = +6.0\,\mu\text{C}

(at

x = 0.40\,\text{m}

) lie on the x-axis. A third charge

q_3 = -4.0\,\mu\text{C}

may be placed at one of three points on the x-axis: (i)

x = 0.20\,\text{m}

, (ii)

x = -0.20\,\text{m}

, or (iii)

x = 0.60\,\text{m}

. Determine at which position the total electric potential energy of the three-charge system is smallest, and support your answer with calculations.