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Temperature of sun-water heating

  • Thread starter Bassalisk
  • Start date
  • #1
948
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Homework Statement


In open wide pot exists a certain amount of water, which has mass m=6,5 kg, which free surface has S=960 cm^2. When this amount of water is exposed to Sun, then its temperature gets higher by deltaT=10 K for time t=30 mins. What is the temperature of Sun?
Sun radiates as absolute black body and that surface of the pot is perpendicular to the sun rays. Absorption of atmosphere of Sun and Earth overrule.

Homework Equations


E=sigma*T^4

The Attempt at a Solution



Problem here is that I am bit confused. Is something missing in this problem? Like some variables? How could I calculate the energy that water received without C(constant of thermal conduction)

Just need a little push here.

Thanks
 

Answers and Replies

  • #2
gneill
Mentor
20,799
2,777
You'll need a few more constants to work this out. You should be able to find the specific heat of water, the distance to the Sun, and the Sun's radius.

If you find the total heat energy absorbed by the water (use the specific heat), and you assume that all the heat entered via the water's surface area, you should be able to calculate the solar constant (W/m^2) and then find the total energy output of the Sun (what's the total energy flux through a spherical surface at the Earth's distance from the Sun?).

What temperature would the Sun have to be in order for it to radiate this amount of energy per unit time over its surface area?
 
  • #3
948
2
You'll need a few more constants to work this out. You should be able to find the specific heat of water, the distance to the Sun, and the Sun's radius.

If you find the total heat energy absorbed by the water (use the specific heat), and you assume that all the heat entered via the water's surface area, you should be able to calculate the solar constant (W/m^2) and then find the total energy output of the Sun (what's the total energy flux through a spherical surface at the Earth's distance from the Sun?).

What temperature would the Sun have to be in order for it to radiate this amount of energy per unit time over its surface area?
Yea I had to take constants out of the table and solve it. Got the result ~6k K
 

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