Allan's answer to Jennifer's Junior College 2 H2 Maths question.

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Allan
Allan's answer
43 answers (Tutor Details)
1st
Be wary what does n stands for in the question
Jennifer
Jennifer
7 years ago
Thanks! May i know why is hf/c is change in momentum?
Allan
Allan
7 years ago
Hi Jennifer. Momentum p=e/c=hf/c.
This formula should be given in your textbook and bear in mind to remember it.
Allan
Allan
7 years ago
However, you must also take note that because photons are absorbed by the surface, change in momentum = hf/c -0. Since there photons do not move after being absorbed.
Allan
Allan
7 years ago
Ask more if in doubt.
Jennifer
Jennifer
7 years ago
I have only learnt momentum =mass x velocity and the eqn for N2L tho
Allan
Allan
7 years ago
Got to bear in mind hf/c is for quantum physics.