A Solid Concrete Wall Has Dimensions 4 $1.3 \mathrm {~W} / \mathrm { m } \cdot \mathrm { K }$

Multiple Choice

A solid concrete wall has dimensions 4.0 m x 2.4 m and is 30 cm thick. The thermal conductivity of the concrete is $1.3 \mathrm {~W} / \mathrm { m } \cdot \mathrm { K }$ and it separates a basement from the ground outside. The inner surface of the wall is at $18 ^ { \circ } \mathrm { C }$ and the outside surface is at $6 ^ { \circ } \mathrm { C }$ How much heat flows through the wall every hour?

A) 5.0 kJ
B) 500 J
C) 5.0 MJ
D) 1.8 kJ
E) 1.8 MJ