Estimate Temperature of Mars Using Sun's Heat

[Manda_24]

Homework Statement

Estimate the temperature of Mars. Assume Mars acts as a perfect blackbody and the only heat input comes from the Sun (use necessary values from appendix)

Homework Equations

The Attempt at a Solution

I was doing so well until I got to this question on my homework.
I tried this: (pi)(r_mars)² / 4(pi)r_sun²

for the radius of Mars my book says 6370 km and the sun 6.95e5 km

 

[mgb_phys]

Thats just one small step in the answer.

First think about what the question means:
How much power does Mars recv from the sun ?
How much power must it emit (and why)
Therefore what temperature must it be?

 

[Manda_24]

We finally talked about this a little in class today, I think. The teacher put up an equation for radiation.
I_emitted=Q/t=eA(sigma)T⁴

Is this part of what I need to use to finish the question? I know what sigma is and e but I don't know what A is.

 

[mgb_phys]

This is the power emitted by a surface of area A at temperature T

Careful - what area of Mars receives energy from the sun and what area emits energy into space?

 

[Manda_24]

Thanks for your help, I finally got it