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Robert Estrada
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Joined: Fri Sep 29, 2017 7:05 am


Postby Robert Estrada » Thu Oct 12, 2017 2:48 pm

Can someone please help with this question:
A lamp rated at 32 W(1W=1 J*s^-1) emits violet light of wavelength 420nm. How many photons of violet light can the lamp generate in 2.0s? How many moles of photons are emitted in that time interval?

Justin Chu 1G
Posts: 52
Joined: Thu Jul 13, 2017 3:00 am
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Re: 1.27HW

Postby Justin Chu 1G » Thu Oct 12, 2017 3:14 pm

If you know 1 Watt = 1 Joule per second, you can figure out that in 2 seconds, you generate 64 Joules of energy. With your wavelength, you can use it to find the frequency as you also know the speed of light constant. After, you can multiply the frequency with Planck's constant to find how much energy (in Joules) is released per photon and divide it from your original total of 64 Joules to find out how many photons were emitted. Then you can just use Avogadro's number to find out how many moles of photons you have.

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