A large body of lava from a volcano has stopped flowing and is slowly cooling. The interior of the lava is at 1250⁰ C, its surface is at 500⁰ C and the surroundings are at 25⁰ C.
a) Calculate the rate at which energy is transferred by radiation from 1m² of surface lava into the surroundings, assuming the emissivity is 1.00.