You want to support a sheet of fireproof paper horizontally, using only a vertical upward beam of light spread uniformly over the sheet. There is no other light on this paper. The sheet measures 20.4 centimeter by 26.4 centimeter and has a mass of 1.54 gram.
A) If the paper is black and hence absorbs all the light that hits it, find what must be the intensity of the light beam?
B) For the light in part (A), determine the maximum value of its electric field?
C) For the light in part (A), determine the maximum value of its magnetic field?
D) If the paper is white and hence reflects all the light that hits it, find what intensity of light beam is needed to support it?
E) To see if it is physically reasonable to expect to support a sheet of paper this way, compute the intensity in a typical 0.500mW laser beam that is 1.00 millimeter in diameter.