The Energy Stored in the Earth's Magnetic Field with a Strength

Multiple Choice

The energy stored in the earth's magnetic field with a strength of 0.5 × 10^-4 T in a room 3.0 m by 4.0 m by 2.4 m is

A) 570 mJ.
B) 29 mJ
C) 10 mJ.
D) 100 mJ.
E) zero.