A +30- $\mu \mathrm { C }$ Point Charge Is Initially Extremely Far from a Positive Point

Multiple Choice

A +3.0- $\mu \mathrm { C }$ point charge is initially extremely far from a positive point charge $Q$ . You find that it takes $41 \mathrm {~J}$ of work to bring the $+ 3.0 - \mu \mathrm { C }$ charge to the point $x = 3.0 \mathrm {~mm} , y = 0.0 \mathrm {~mm}$ and the point charge $Q$ to the point $x = - 3.0 \mathrm {~mm} , y = 0.00 \mathrm {~mm}$ . What is $Q$ ? $( k = \ldots )$

A) $4.6 \mu \mathrm { C }$
B) $55 \mathrm { nC }$
C) $27 \mathrm { pC }$
D) $9.1 \mu \mathrm { C }$