22.1e Ex4 ON19 P41 Q11 Energy Changes in Emission | A2 Quantum Physics | Cambridge A Level Physics

[@Anzaedits]

I love this woman

[@yangsita6201]

Thanks for your amazing lecture,but I have one doubt. I learned in another lecture that number of ejected electrons is independent of the frequency of photon(light) at a constant intensity. I fully understand your method,but this still seems very paradoxical for me.

[@nawfaljafri]

intesnity is bascailly dependent on two things: number of electrons released and Energy ( or frequency sicne E = hf so since h is a constant, e is proportional to f, therefore you could also consider frequency instead of E too), now if intensity is constant, then as number of electrons change, frequency will change in the opposite way (one will icnrease and the other will decrease). changing frequency effects the energy of ur particle released but not the number of particles realsed (hence, what you heard in another lecture, that they're independent) but i wouldn't use the word independent, rather, one doesnt cause the other, but they're both still related to intensity, so in order to keep intensity of something the same, you would have to re adjust number of particles & the frequency to keep the numbers the saem if that makes snese

[@yangsita6201]

In that lecture,they plot a graph of number of ejected electrons against the frequency of light,turns out the graph is simply a horizontal line.

[@ETphysics]

we are making the assumption that intensity of EM wave is constant, hence less photons per unit time, so less ejected electrons. the lecture could also make the assumption that the no of photon per unit time is the same - same ejected electrons (ie by increasing the the Intensity) You can watch a more detailed explanation here kzbin.info/www/bejne/nILEdnuEprKrrdk