Hey guys, I'm having a problem with some test review stuff, and even though I've looked through my notes and book, I can't find anything similar to this problem.
Ok, so I know that E= hc/(lambda), but I don't really know how to fit that in with the problem. h = 6.63E-34 and c = 3E8
The problem is: A stellar object is emitting radiation at 1000 nm. If the detector is capturing 4E7 photons per second at this wavelength, what is the total energy of the photons detected in a period of one hour?
I can't figure out what to do with the 4E7. This is what I did, but I'm pretty sure it isn't right unless they're just giving extra numbers to be confusing.
E=hc/(lambda)
E = (6.63E-34)(3E8)/(1E-6)
E = 1.986E-19 J/hr
total energy of photons
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Ok, the E=hc/lambda is the energy of one photon.
The amount of photons emitted is 4E7. This tells you to multiple your energy of a photon with the number of photons:
E total = [hc/1000nm)*4E7]
= [(6.626E-34 Js)(3E8 m/s)/(1E-6m)*(4E7)]
= 7.95E-12 J/s
Now, multiply by 3600 (3600s per hour) and that't the overall energy.
The numbers might be a bit off depending on how many sig figs you use but that should be the answer.
Hope it helped
The amount of photons emitted is 4E7. This tells you to multiple your energy of a photon with the number of photons:
E total = [hc/1000nm)*4E7]
= [(6.626E-34 Js)(3E8 m/s)/(1E-6m)*(4E7)]
= 7.95E-12 J/s
Now, multiply by 3600 (3600s per hour) and that't the overall energy.
The numbers might be a bit off depending on how many sig figs you use but that should be the answer.
Hope it helped