Understanding Photon Energy: Help Needed for Chemistry Student

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Homework Help Overview

The discussion revolves around understanding the energy of a photon, particularly the derivation involving angular frequency (ω) and its relationship to wavelength and energy. The original poster, a chemistry student, expresses confusion regarding the use of ω in the context of photon energy equations.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants discuss the meaning of angular frequency and its distinction from regular frequency. There is an exploration of how spectroscopists use ω in their work, particularly in relation to wavenumber and frequency. The original poster questions the derivation process and the notation used by their lecturer.

Discussion Status

Some participants have provided clarifications regarding the notation and its usage in spectroscopy. There is an ongoing exploration of the definitions and relationships between frequency, angular frequency, and energy, but no consensus has been reached on the original poster's confusion.

Contextual Notes

The original poster indicates a lack of familiarity with physics terminology as a chemistry student, which may be influencing their understanding of the derivation. There is also mention of potential notation confusion that could affect the interpretation of the equations involved.

Randomchemstudent
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Homework Statement
w/v=c,w=vc giving E=hcv
Relevant Equations
E=hw, lamda*w=c, wavenumber (v) = 1/lamda
So I'm a chemistry student here in the UK - and I'm feeling a bit like a fish out of water on a physics forum but... I'm having trouble with a derivation that seems simple but i can't for some reason seem to understand.

I know that the energy of a photon is given by E=hc and that c=lambda*v giving E=hc/lamda. But my lecturer has used w(omega) in his derivation and i don't understand what it means and why he's used it to derive the energy in this way.

Any help would be much appreciated!
 
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##\omega## is angular frequency. It differs from frequency by a factor of ##2\pi##.
 
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Spectroscopists often use ω for frequency, or for wavenumber. They (we) often loosely talk about wavenumber as frequency, e.g. "a frequency of 1730 cm-1". For example, on the NIST website, molecular vibrational frequencies in cm-1 are given the symbol ω. So you have to be a bit careful.
 
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Randomchemstudent said:
Problem Statement: w/v=c,w=vc giving E=hcv
Relevant Equations: E=hw, lamda*w=c, wavenumber (v) = 1/lamda

I know that the energy of a photon is given by E=hc
No. The energy of a photon is ##hf##, which is often written as ##h \nu##, where ##f## or ##\nu## is the frequency. You seem to have your notation mixed up.
 

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