The Radius of a Star Is $6.95 \times 10 ^ { 8 } \mathrm {~m}$

Multiple Choice

The radius of a star is $6.95 \times 10 ^ { 8 } \mathrm {~m}$ and its rate of radiation has been measured to be $5.32 \times 10 ^ { 26 }$ W. Assuming that it is a perfect emitter, what is the temperature of the surface of this star? $( \sigma =$ $\left. 5.67 \times 10 ^ { - 8 } \mathrm {~W} / \mathrm { m } ^ { 2 } \cdot \mathrm { K } ^ { 4 } \right)$

A) $3.93 \times 10 ^ { 7 } \mathrm {~K}$
B) $8.87 \times 10 ^ { 3 } \mathrm {~K}$
C) $8.25 \times 10 ^ { 3 } \mathrm {~K}$
D) $5.78 \times 10 ^ { 7 } \mathrm {~K}$
E) $6.27 \times 10 ^ { 3 } \mathrm {~K}$