- #1
pokemon123
- 5
- 2
Homework Statement
I have been asked to calculate the momentum of a photon in that has been ejected as a gamma ray after a nucleus was excited in terms of the Energy. I am confused as to whether or not I can use two different equations
Homework Equations
E=mc^2 or E=hf λ=h/p
The Attempt at a Solution
E=mc^2 E/c=mc
mv=p
c=v(of photon)
thus E/c=p
E=hf
f=v/λ
λ=hc/E
λ=h/p
h/p=hc/E
p=E/c
where I get confused is that the answer sheet only gives the second derivation as the answer and i have been told by someone that E=mc^2 is not the correct way to derive the momentum of a photon however I'm not sure why. Could someone please explain to me if both derivations are correct or if one is incorrect please explain why.