- #1

Aurora_b

- 4

- 3

- Homework Statement
- Why KE_(max) depends on frequency but doesn't depend on intensity? (This isn't exactly my homework but a related conceptual doubt i have in order to solve the homework questions)

- Relevant Equations
- So the confusion arose when my teacher wrote the equation for photoelectric effect:

KE_max = hf - W ------ eqn 1)

where,

KE_max = maximum kinetic energy of ejected electrons.

f= frequency of incident radiation

W= work function of the metal

Then the teacher wrote the formula for intensity

I = Nhf/A ------- eqn 2)

where,

N = no of photons incident per unit time

f= frequency of incident radiation

A= Area

Then the following statement was made:

Statement 1: KE_max depends on frequency but doesn't depend on Intensity.

I would believe the last statement if Intensity only depended on N but it also depends on the frequency f. Now if Intensity depends on f we can also find a relationship between KE_max and Intensity by substituting from eqn 2) in eqn 1)

KE_max = IA/N - W

So if KE_max depends on f and I depends on f then we can find the dependence between KE_max and I.

I understand I am wrong and that statement 1 is correct but I am just unable to convince myself, because everyowhere the reasoning is that I depends on N so it is independent but I also depends on f. Please help me understand.

KE_max = IA/N - W

So if KE_max depends on f and I depends on f then we can find the dependence between KE_max and I.

I understand I am wrong and that statement 1 is correct but I am just unable to convince myself, because everyowhere the reasoning is that I depends on N so it is independent but I also depends on f. Please help me understand.