Threshold Energy [ENDORSED]

[Priscilla Okaiteye]

I know this was covered in lecture but I'm still a bit confused. What exactly is the threshold energy and how does it relate to quantum equations?

[Vivian Gonzalez 1A]

Threshold energy is the amount of energy needed to eject an electron from a metal.

[Neha Divi 1K]

To add on, the photoelectric effect is the idea that there is an ejection of electrons from a metal when its surface is exposed to ultraviolet radiation. Furthermore, no electrons are ejected unless the radiation has a frequency above a certain threshold that is characteristic of a metal.

[Jada Larson 1F]

The equation related to threshold energy is:
E_photon - E_{required to eject electron} = E_excess

E_photon=hv. [*]h = 6.626 x 10^-34 Js and [*]the v is frequency
E_{required to eject electron} is called the threshold energy or the work function, and it is represented by the symbol ϕ.
E_excess equals E_K = (1/2)mv². [*]note: the v is for velocity, not frequency

[Cameron Smith 1I]

What occurs to the kinetic energy that is the excess when the energy of the photon is greater than the threshold energy?

[Alma Flores 1D]

In Friday's lecture, Dr. Lavelle mentioned that the energy of of the photon is equal to the sum of the threshold energy and the kinetic energy.

[Sonia Aronson 1B]

The threshold energy is the minimum amount of energy required to move an electron from the surface of a metal.

[Isobel Tweedt 1E]

How does this relate to the concept of darkness versus lightness? Does the release of electrons result in our viewing of light and the color spectrum?

[004985802]

it is the energy required to move an electron from one state (energy level) to the next. If the input energy is less than threshold, the electron will remain at the same state (energy level).

[breannasung_1K]

Threshold energy is the amount of energy needed to remove an electron from the metal.

[AnnaYan_1l]

What occurs to the kinetic energy that is the excess when the energy of the photon is greater than the threshold energy?

I believe that in the photoelectric experiment, this kinetic energy is detected by a detector which shows the excess energy of the photon that surpassed the threshold energy (since kinetic energy = energy of the photon - threshold energy (also known as work function)).

[NabilaNizam-1K]

What affects the threshold energy of a photon?

[Caroline Crotty 1D]

A threshold energy is specifically effected by what metal you are attempting to eject an electron from. Think of threshold energy almost as ionization energy, each metal will have its own specific threshold energy to have a single electron ejected.