At a Distance D from a Point Charge Q, the Energy

Multiple Choice

At a distance d from a point charge Q, the energy density in its electric field is u. If we now go to a distance d/2 from the charge, what is the energy density at the new location?

A) 16u
B) 8u
C) 4u
D) 2u
E) u $\sqrt { 2 }$