light........physics help?

Question

1.) The intensity of solar radiation varies inversely with the square of the distance from the sun. The earth is an average of 1.5 x 10^8 km from the sun.

How close to the sun should the earth be for the solar radiation pressure to be 1.0 Pa?

Answer 1

Radiation pressure..Hmmm...
Photonic radiation not much at all.
Particle radiation that is a different story.
The ions leaving the Sun are 95% singly ionized hydrogen, 4% doubly ionized helium, and less than 0.5% other ions .
also
Near Earth, the velocity of the solar wind varies from 200 to 889 km/s. The average is 450 km/s. Approximately 1×109 kg/s of material is lost by the Sun as ejected solar wind,


Assuming only hydrogen the pressure is

P=(p/t)/A= mv/(t A)
A=4piR^2
P=(m/t)v/(4piR^2)
R=sqrt(m/t)v/(4piP))

Let v=500km/s
m/t= 1×109 kg/s
P= 1Pa

Just compute