Calculating the Sun's Power Output

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To calculate the Sun's power output, the intensity of electromagnetic waves at Earth's upper atmosphere is given as 1.4 kW/m². The formula I = P/A is used, where I is intensity, P is power, and A is the surface area of a sphere with radius equal to the distance from the Earth to the Sun. By rearranging the formula, the total energy emitted by the Sun can be calculated using the surface area of the sphere (4πr²) and the given intensity. The final step requires plugging in the distance from the Earth to the Sun in meters to find the power output in watts.
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Homework Statement



The Sun emits electromagnetic waves (including light) equally in all directions. The intensity of the waves at the Earth's upper atmosphere is 1.4 kW/m2. At what rate does the Sun emit electromagnetic waves? (In other words, what is the power output?)
____ W


Homework Equations



?

The Attempt at a Solution



I have no idea how to do this one...

I know it involves I = P/A
 
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If r is the dist of Earth from sun, then total energy W emitted by sun in one second will fall on the surface of a sphere of radius r in one second (after 8.3 mins or so).

W/(4*pi*r^2) = 1.4*10^3 (given). You have to plug in the value of r in meters. That's all.
 

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