Process of Science: The theory of thermal radiation says that hot ...

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Process of Science: The theory of thermal radiation says that hot objects are bluer than cool objects. Does it depend on what the object is made of? How can you test this?
 
  What will be an ideal response?

Question 2

Which of the following best explains the phenomenon of black hole evaporation?
 
  A) Due to high temperatures in the accretion disk around a black hole, material evaporates from the black hole like water evaporating from the ocean.
  B) Particles (or antiparticles) are occasionally ejected from within the event horizon, causing the black hole to lose mass.
  C) Particles (or antiparticles) are created by a quantum mechanical effect near, but outside, the event horizon of the black hole. The law of conservation of energy maintains that the black hole must lose energy to pay for the creation of this mass.
  D) Virtual particles created near the black hole are constantly annihilating each other, causing a very high temperature even if the black hole has no accretion disk. This high temperature provides escape velocity for the virtual particles, causing the entire cloud of virtual particles to expand away into space.
  E) Black hole evaporation is a virtual process, meaning that it has been theorized by astrophysicists but doesn't really occur.

[duy1981999]

Answer to Question 1

The color of thermal radiation from an object does not depend on its composition. You can test this by heating two pokers, one made of iron, another of, say, copper. They would each have the same white hot glow, turning to red hot as they cooled down (although the rate at which they cooled down and therefore their color at the same time after they are out of the fire would be different).

Answer to Question 2

C

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