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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: Zeugma on October 10, 2009, 10:02:23 AM

Title: Calculating the Energy of a Photon
Post by: Zeugma on October 10, 2009, 10:02:23 AM

Hi there!

I'm in need of some homework help:

A mercury atom drops from 1.413 x 10^-18 J to 1.069 x 10^-18 J. What is the energy of the photon emitted by the mercury atom?

I know how to use E_photon to find energy but only when the frequency is given. Why are there two figures given in the question and what do I do with them?

Thank you.

Title: Re: Calculating the Energy of a Photon
Post by: cliverlong on October 10, 2009, 04:38:05 PM

You are given a start energy value and a finish energy value. Which arithmetic operation do you think you need to calculate an energy from these two values?

Clive

Title: Re: Calculating the Energy of a Photon
Post by: Zeugma on October 10, 2009, 09:26:36 PM

Quote from: cliverlong on October 10, 2009, 04:38:05 PM

You are given a start energy value and a finish energy value. Which arithmetic operation do you think you need to calculate an energy from these two values?

Clive

Subtraction! (I just subtract them?)

Title: Re: Calculating the Energy of a Photon
Post by: cliverlong on October 11, 2009, 02:23:54 AM

Seems reasonable to me.