In the 25-ft Space Simulator facility at NASA's Jet Propulsion Laboratory, a bank of overhead arc lamps

Question:

In the 25-ft Space Simulator facility at NASA's Jet Propulsion Laboratory, a bank of overhead arc lamps can produce light of intensity 2500 W 1m' at the floor of the facility. (This simulates the intensity of sunlight near the planet Venus.) Find the average radiation pressure (in Pascals and in atmospheres) on
(a) A totally absorbing section of the floor and
(b) A totally reflecting section of the floor.
(c) Find the average momentum density (momentum per unit volume) in the light at the floor.