A

To find the temperature of the sun's surface, we use the formula relating the power per unit area (solar constant) with the Stefan-Boltzmann Law: \[ P = \sigma T^4 \] Where: - \( P \) is the power per unit area received at earth, which is \( 1.362 \times 10^3 \, \text{J/m}^2\text{s} \) - \( \sigma \) is the Stefan-Boltzmann constant, \( 6 \times 10^{-8} \, \text{W/m}^2 \, ext{K}^4 \) - \( T \) is the absolute temperature of the sun. First, we rearrange the equation to find \( T \): \[ T = \left( \frac{P}{\sigma} \right)^{1/4} \] Now, substituting the values: \[ T = \left( \frac{1.362 \times 10^3}{6 \times 10^{-8}} \right)^{1/4} \] Calculating the expression inside the parentheses: \[ \frac{1.362 \times 10^3}{6 \times 10^{-8}} = 2.27 \times 10^{10} \] Now, taking the fourth root: \[ T = \left( 2.27 \times 10^{10} \right)^{1/4} \approx 6.54 \times 10^2 \text{K} \approx 654 ext{K} \] This value can be rounded to approximate the sun's surface temperature. Therefore, our answer is close to 654 K.