# Simple question on number of photons per second

1. Feb 22, 2013

### Fluxthroughme

Part a) is correct, but the book gives me an answer of $2.3*10^{23}$ for part b. Is the book wrong or have I missed a factor of 1000 somewhere?

2. Feb 22, 2013

### Staff: Mentor

3. Feb 22, 2013

### Fluxthroughme

I'm going to have to conclude the book has the wrong answer, then. Thanks :)

4. Feb 22, 2013

### Naty1

goo job......

What did you conclude regarding question [c]???

5. Feb 22, 2013

### Fluxthroughme

The answer is no, they are not the same. I am not 100% sure why it is even asking this. As far as I can venture a guess, I would say that the word 'frequency' would make some people think of the number of photons emitted per second, and would thus get it confused. However, the frequency of a photon is of A photon, not a bunch of them. Thus, some might think it meant frequency as it "The frequency with which photons are emitted". This clearly isn't the case, though I can understand there is room for confusion.

Would this be correct? As I say, I'm not 100% sure why this is asked; my answer makes sense to me, but it doesn't seem the kind of thing that needs explaining.

6. Feb 22, 2013

### Naty1

That's basically how I would respond...I think the question just aims at verbalizing the math perspectives.

You can easily change the the number of photons emitted, the power radiated,
by increasing the current. Depending on how you look at it, that would increase
the number of photons but not the frequency...at least as posed in this problem.

In the real world, a hotter bulb likely generates a higher frequency wavelength
AND more photons, but they ARE different concepts as you explain.