A small spherical satellite is in circular orbit round the Sun. The Sun subtends at the satellite

Question:

A small spherical satellite is in circular orbit round the Sun. The Sun subtends at the satellite a solid angle of 7 × 10–5 steradians, and the temperature of the satellite is uniform. Assuming that the emissivity of the satellite is independent of wavelength, calculate this temperature. (The effective black-body temperature of the sun’s surface is 5800 K.)