In the 25 ftft Space Simulator facility at NASA's Jet Propulsion Laboratory, a bank of overhead arc lamps can produce light of intensity 2500 W/m^2 at the floor of the facility. (This simulates the intensity of sunlight near the planet Venus.) Required:
Find the average radiation pressure (in pascals and in atmospheres) on

a. A totally absorbing section of the floor.
b. A totally reflecting section of the floor.
c. Find the average momentum density (momentum per unit volume) in the light at the floor.

a) 8.33 x Pa  or  8.22 x atm

b) 1.66 x Pa  or  1.63 x atm

c) 2.77 x kg/m^2-s

Explanation:

Intensity of light = 2500 W/m^2

area = 25 ft^2

a) average radiation pressure on a totally absorbing section of the floor

where I is the intensity of the light

c is the speed of light =

= 8.33 x Pa

1 pa =

8.33 x Pa = 8.22 x atm

b) average radiation for a totally radiating section of the floor

this means that the pressure for a totally radiating section is twice the average pressure of the totally absorbing section

therefore,

Pav = 2 x 8.33 x  = 1.66 x Pa

or

Pav in atm = 2 x 8.22 x = 1.63 x atm

c) average momentum per unit volume is

= 2.77 x kg/m^2-s

what was the answer?