How Many Photons Does the Sun Emit Daily?

AI Thread Summary
The sun emits 3x10^32 J of energy daily, and the energy of each photon of yellow light, calculated using E = hf, is approximately 3.3x10^-19 J. To determine the number of photons emitted daily, the total energy output should be divided by the energy per photon. However, confusion arises when incorrect units are used, leading to an invalid calculation. The correct approach requires ensuring the final answer is expressed in units of "photons."
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Homework Statement


The sun emits 3x1032J of energy every day. Assume it emits only yellow light (6x10-7m wavelength. a. What is the energy of each photon of yellow light? b. How many photons does the sun emit every day?


Homework Equations



E = hf

The Attempt at a Solution


So I think I have question A complete, my solution is the following.
F = (3x108 m/s)/(6x10-7 m) = 5x1014 Hz
H = (6.6x10-34Js)
E=h*f (6.6x10-34Js)(5x1014Hz) = 3.3x10-19 J
Or E = 2 eV

But problem B I am stumped. I don't even know where to begin to figure this out. Can anyone help put me in the right direction?
 
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You computed the energy of a single photon in J. You have the total energy output of the sun (n photons) in a day also in J. You seem pretty close to an answer.
 
So the answer is 9.9x1013 photons?
 
If you multiply 3x1032J and 3.3x10-19 J/photon, the result is 9.9x10^13 J2/photon.

Those units, J2/photon, do not make any sense. So no, that is not it.

Since the question asks for the number of photons, you're looking for an answer with units of "photons" in it.
 
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