Midterm 1

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MaryBanh_2K
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Joined: Wed Sep 18, 2019 12:21 am

Midterm 1

Postby MaryBanh_2K » Thu Nov 07, 2019 9:43 am

How do you find the number of photons a light can generate if you are given the amount of energy the light emits and its wavelength?

SnehinRajkumar1L
Posts: 101
Joined: Thu Jul 11, 2019 12:15 am

Re: Midterm 1

Postby SnehinRajkumar1L » Thu Nov 07, 2019 10:08 am

Given the energy for exciting one electron, divide the energy absorbed by that value.

SarahSteffen_LEC4
Posts: 67
Joined: Sat Aug 24, 2019 12:17 am

Re: Midterm 1

Postby SarahSteffen_LEC4 » Thu Nov 07, 2019 10:09 am

I struggled on this question also, but now looking back at it, I think you would calculate the energy per photon required, using the equation E=hv or E=hc/lambda. And once you find that, I believe you would divide the energy that was given to you (in Joules) by the calculated energy you just found (joules/photon), canceling out the Joules, leaving you with the number of photons. This could be wrong though. I'm not for sure.

Michelle Chan 1J
Posts: 50
Joined: Thu Jul 25, 2019 12:16 am

Re: Midterm 1

Postby Michelle Chan 1J » Thu Nov 07, 2019 11:06 am

I also struggled with this. I was thinking it has something to do with Avogadro's number? I'm not completely sure.

Emily Vainberg 1D
Posts: 102
Joined: Sat Jul 20, 2019 12:15 am

Re: Midterm 1

Postby Emily Vainberg 1D » Thu Nov 07, 2019 11:23 am

I also was confused on this question. I believe you were suppose to use the energy found in the previous problem, and relate this to the number of photons using Avogadro's number. Then once you had the photons convert to moles of Hydrogen atoms using the grams per mole of hydrogen.

Deana Moghaddas 3E
Posts: 51
Joined: Fri Aug 30, 2019 12:17 am

Re: Midterm 1

Postby Deana Moghaddas 3E » Thu Nov 07, 2019 11:42 am

Anyone know when we'll get the midterm grades back?

Emily_4B
Posts: 57
Joined: Wed Sep 18, 2019 12:21 am

Re: Midterm 1

Postby Emily_4B » Thu Nov 07, 2019 7:08 pm

Do you guys know if we’ll get the midterm back or be able to look at it in office hours to review this question?

AngieGarcia_4F
Posts: 120
Joined: Thu Jul 25, 2019 12:17 am

Re: Midterm 1

Postby AngieGarcia_4F » Thu Nov 07, 2019 7:10 pm

Emily_4B wrote:Do you guys know if we’ll get the midterm back or be able to look at it in office hours to review this question?

My TA went over the midterm during discussion so maybe yours will too.

Emily_4B
Posts: 57
Joined: Wed Sep 18, 2019 12:21 am

Re: Midterm 1

Postby Emily_4B » Thu Nov 07, 2019 7:12 pm

AngieGarcia_4F wrote:
Emily_4B wrote:Do you guys know if we’ll get the midterm back or be able to look at it in office hours to review this question?

My TA went over the midterm during discussion so maybe yours will too.

That sounds really helpful, thanks!

Diana_Diep2I
Posts: 130
Joined: Sat Aug 17, 2019 12:17 am

Re: Midterm 1

Postby Diana_Diep2I » Fri Nov 08, 2019 9:51 am

Emily_4B wrote:Do you guys know if we’ll get the midterm back or be able to look at it in office hours to review this question?

I was told that we would get our midterm back next Wednesday during lecture.


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