When light falls on a perfect absorbing surface (i. e. a surface the completely absorbs all the light), the amount of momentum transferred in a tune delta t is given by delta p = ac delta t where a is the surface area illuminated, c is the velocity of light, and is the momentum density earned by the electromagnetic wave which from class you may remember was given by where the intensity is given by = 1/c^2 i where the intensity is given by i = |s| where s is the poynting vectore. the pressure p (force per unit area) is defined as the amount of momentum transferred to the material per unit area per unit time. in other words, p = 1/a delta p/delta t = i/c the above equation lets you calculate the "radiation pressure" for an electromagnetic field. the intensity of sunlight hitting the earth is about 1300 w/m^2. if sunlight strikes a perfect absorber, calculate the pressure it absorbs? now repeat the calculation above for a perfect reflector. for each case, calculate the fraction of atmospheric pressure this corresponds to.