Describe the physics of the following?

Question

1. a) Describe the process(es) by which (i) energy is produced in the Sun (ii) energy is transferred from the Sun to Earth.
b) Compare the heat radiated by a hot body with the light emitted from a lamp under the following headings:
(i) speed of travel (ii) ability to pass through a vacuum (iii) ease with which they are reflected (iv) ease with which they are absorbed.

Answer 1

ai) Nuclear fusion
aii) via electro-magnetic wave
bi) Traveling speed is the same c for heat radiation: the speed of the light, or electro-magnetic wave
bii) 100% pass through a vacuum
biii) depends on surface color and surface roughness. Generally heat is easier to be reflected than the visible light.
biv) depends on material. Some material is (relatively) transparent to heat (such as silicon), some material is more transparent to visible light (such as glass). Also, light is easier to be absorbed by rough surface.