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### Post Module #19

Posted: Mon Oct 16, 2017 7:46 pm
Which one of following is not describing the photoelectric effect?

A. E (photon) – E (remove e-) = E (excess)
B. E (photon) – E (remove e-) = EK (e-)
C. hv - work function = 1/2mv2
D. λv = c
E. None of the above

What is the answer to this and can someone explain why? Thanks!

### Re: Post Module #19

Posted: Mon Oct 16, 2017 8:30 pm
The photoelectric effect shows that light (electromagnetic radiation) acts as particles with particle-like properties. Therefore, d would not explain the photoelectric effect because d is an equation for wave-like properties, like wavelength.

### Re: Post Module #19

Posted: Mon Oct 16, 2017 8:33 pm
I believe the answer is D! A, B, and C all describe the same equation, which has to do with the photoelectric effect. The equation for D was not derived as a result from the photoelectric experiment!

### Re: Post Module #19

Posted: Mon Oct 16, 2017 8:36 pm
In order to understand the question, it is necessary to understand how the photoelectric effect works. Basically, light is shone on a metal, and the metal emits electrons. However, the appropriate frequency and therefore energy of light that is needed to knock off electrons is different for every substance. Answers A, B, and C all depict how the energy of a photon is used to remove an electron (with the excess energy existing as the kinetic energy of the emitted electron). Answer D is simply depicting the relationship between the wavelength and frequency of light, so it is the correct answer.