Solar luminosity

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  • #1
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Homework Statement


The formula for the surface area of a sphere is 4(3.14) r2, where r is the mean distance from the sun to the earth. Determine the sphere of light (square meters) illuminated by the sun the size of the earth's orbit.


Homework Equations



astronomical Unit-149,597,829 k

The Attempt at a Solution


my answer is 2.8122922(17)
no idea
 
Last edited:

Answers and Replies

  • #2
Delphi51
Homework Helper
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Welcome to the Physics Forum, newsflash!

S = 4(3.14) r^2
= 4*3.14*(149,597,829 km)^2
= 2.81 x 10^15 km^2
If you need that in square meters, I suggest you change the r value into meters before squaring. It is tricky changing units on something after it is squared.
 

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