Question

Calculate the energy in J of 0.32 moles of photons whose frequency is 2.6 x 10^15?

Answer 1

Have any ideas so far?

Answer 2

Convert the moles to photons?

Answer 3

That would be a fine starting point. :)

Answer 4

Then what would I do after that?

Answer 5

Well, that action would give us the total number of photons we are looking at.
In a sense the energy should then be the energy of one individual photon times how many we have.

Answer 6

Could you explain how to calculate that please? I am just having some trouble understanding this topic..

Answer 7

Well, we are given a frequency. We need to find the energy.
Do you recall seeing these two formulas:
E = h v
h is planck constant, v is frequency <-- we need frequency here...
c = w v
c is speed of light, w is wavelength, v is frequency <-- this is to convert frequency and wavelength

Answer 8

Yes

Answer 9

So, the procedure is like this:
(a) Convert the wavelength 2.6 x 10^15 to frequency (c = w v)
(b) Use frequency and Planck constant to find Energy (E = h v = h c/w )

Answer 10

Ok, thank you!

Answer 11

Glad to help!
and once you find energy there, don't forget to multiply by the number of photons to get the overall energy.

Answer 12

Ok, I wont forget

Answer 13

The question already provides the frequency. So you can straight find the energy of one photon with the formula AD provided.

Answer 14

oh wow, i entirely just imagined this question saying we had wavelength. :x
thanks for pointing it out @iPwnBunnies

Answer 15

so its actually easier than that, skip (a) because we have frequency
E = h v
sorry for the mix up!