Question

Recall that force is a change in momentum over a change in time, the force due to radiation pressure reflected off of a solar sail can be calculated as 2 times the radiative momentum striking the sail per second. What is the approximate magnitude of the pressure on the sail in the vicinity of Earth’s Orbit?

Answer 1

Answer:

magnitude of the pressure on the sail in the vicinity of Earth’s Orbit= $\frac{2I}{c}$

Explanation:

The momentum of a photon is:

p = E/c

E = the photon energy

c = the speed of light.

take the time derivative (gives the force)

F = dp/dt = (dE/dt)/c

F = 2(dE/dt)/c (is doubled for complete reflection of the light)

Intensity has the units of energy per unit time per unit area

=  I

then,

Force/unit area = 2I/c

magnitude of the pressure on the sail in the vicinity of Earth’s Orbit= $\frac{2I}{c}$