Objects can be categorized as blackbodies (emissivity $\epsilon = 1$), grey bodies (emissivity $\epsilon < 1$) and white bodies (emissivity $\epsilon = 0$).
If we placed two objects (identical shape), one black and one white, in sunlight for a very long time (say 15 hrs), what would happen?
1) I think both objects would absorb radiation from the sun and their temperatures would increase until they reach their final temperatures.
2) The final temperature for the white object is lower than for the black object.
3) The white object will take longer than the black object to reach its final temperature.
4) The black object behaves like a blackbody. Blackbodies are said to be perfect emitters and perfect absorbers. But even a white object reflects (in theory) all the incident energy. So what is the difference? That reflection does not contribute to raising the T of the object?
5) In some cases, two different objects, left in the same room, reach the same temperature as the room. Why doesn't that happen when the same two object are left under the sun? What if they were left in the shadow? Would they eventually have the same temperature?