Two point charges and are placed apart on a straight line

PHYSICS · Single correct · AP · Physics 2: Algebra-based · Electric Force Field and Potential · Electric Force Field and Potential

Problem

Two point charges

+4\,\mu\text{C}

and

+1\,\mu\text{C}

are placed

60\ \text{cm}

apart on a straight line. How far from the

+1\,\mu\text{C}

charge, measured along the line joining them, should a third small positive charge be placed so that it experiences zero net electrostatic force? (a)

12\ \text{cm}

(b)

40\ \text{cm}

(c)

20\ \text{cm}

(d)

30\ \text{cm}