Photoelectric Effect

$c=\lambda v$

Layal Suboh 1I
Posts: 61
Joined: Fri Sep 28, 2018 12:23 am

Photoelectric Effect

Hello,

I'm a little confused about the process of the photoelectric experiment. I know that through this experiment, light was shown to be a particle, but how exactly was this experiment conducted so that the quantum mechanic description of light was proven?

Thank you!

MaanasO 1A
Posts: 72
Joined: Fri Sep 28, 2018 12:26 am

Re: Photoelectric Effect

Hi!

From what I understand, the photoelectric effect wasn't tested through an experiment to prove its existence. A group of scientists attempted to observe incandescence, the phenomenon of an object glowing when it's really hot. Because classical physics could not yield equations that could explain the observations found from these experiments, Max Planck tried a different approach by saying that energy is transferred in finite amounts. His equations worked out to match the data almost identically.

In this case, scientists found inexplicable data and then came to a conclusion using logic to explain that data.

Hope that helps!

Aria Soeprono 2F
Posts: 64
Joined: Fri Sep 28, 2018 12:27 am

Re: Photoelectric Effect

According to the lecture, the photoelectric experiment involved shining UV light on a metal surface to measure the required energy to remove electrons from different types of metals. Using the wave model for light, scientists expected that with increased intensity, the metal would emit more electrons. However, this was not the case because of the photoelectric effect, in which each photon (rather than the hypothesized wave of light), needs enough energy to remove one electron in a 1:1 ratio, so regardless of how many photons are involved, if none of them have enough energy (high enough frequency), then no electrons will be removed.