Homework Help: Radiation problem

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1. Sep 19, 2015

Physics-101

1. The problem statement, all variables and given/known data
We have a sensor onboard a satellite that is faced towards Earth, from the Sun. The LW absorptivity is 0.8 (a_LW) and SW is 0.2 (a_SW).
I need to find a equation for the temperature as a function of time. Given datas is the Area=0.3 m^2 and Specific Heat of 4 J/K

2. Relevant equations
See below.

3. The attempt at a solution
I think that I need to calculate the equilibrium temperature, which I did by using T=((a_sw/a_LW)*(Fs/omega))^1/4,
Fs=solar flux=1368 W/m^2 and omega= Stefan-Boltsmann constant.

Later, one equation that I have in mind for the temperature as a function of time is:
m*c*(dT/dt)=A*omega*T^4 , where A= area and m= mass. The sensor might be really small, so the mass m is negligible (?). What should I do now, I'm stuck.

Thanks!

2. Sep 24, 2015

Staff: Admin

Have you thought of anything else to help solve the problem?

3. Sep 24, 2015

Staff: Mentor

A negligible mass is equivalent to a satellite that is always at its equilibrium temperature .

You'll have different areas for absorption of sunlight and emission of infrared light, and those areas depend on the orientation of the satellte.

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