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Energy from the sun

  • Thread starter bon
  • Start date
  • #1
bon
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Homework Statement



Energy from the sun (distance 1.496 x 10^11m from earth) arrives at the earth at a rate of 1400W/m^2. How fast is the sun losing mass due to energy radiation?

Homework Equations





The Attempt at a Solution



Ok so i thought that Ei = E/r^2 where Ei is incident radiation and E is radiation at source..

Therefore E sun = r^2 (1400)

Then using E=mc^2..I divide the result by c^2 to give mass loss per second..

but i don't get the right answer..where am i going wrong?
thanks
 

Answers and Replies

  • #2
Filip Larsen
Gold Member
1,237
169
The solar constant specifies how much power sun light contains per square meter at our distance from the sun. To get the total power output of the sun light you would then need to know "how many" square meters there are all around the sun at our distance from it.
 
  • #3
Doc Al
Mentor
44,882
1,129
You are given the power per unit area at a certain distance from the sun. What's the total area over which the sun's energy is spread at that distance? (You're almost there.)
 

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