solve this problem

1. The Sun has a surface temperature of 5770 K. A. At what wavelength does the Sun radiate most per unit wavelength? B. Use Stefan's Law to determine the rest mass lost per second to radiation. Take the diameter of the Sun to be 1.39 x 10 m. C. The Sun's rest mass is 2.0 x 10? kg. What fraction of the Sun's rest mass is lost per year from radiation