Photoelectric effect white light

Click For Summary

Homework Help Overview

The discussion revolves around the photoelectric effect, specifically analyzing the emission of electrons from a metal surface when exposed to white light with a specified range of wavelengths. The original poster presents a calculation involving the maximum kinetic energy of emitted electrons, given a work function.

Discussion Character

  • Exploratory, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • Participants discuss the relationship between photon energy, wavelength, and the work function of the metal. There is an exploration of how to calculate the maximum kinetic energy of the emitted electrons using the energy of the photons and the work function.

Discussion Status

The conversation includes attempts to clarify the calculations involved in determining the maximum kinetic energy of the electrons. Some participants confirm the calculations of photon energy and its relationship to the work function, while others seek to verify their understanding of the steps needed to arrive at the kinetic energy value.

Contextual Notes

Participants are working with specific values for the work function and the energy of photons, and there is a focus on ensuring the correct application of the formulas related to the photoelectric effect. The discussion reflects a need for clarity on the units involved and the calculations required to derive the kinetic energy.

Alt+F4
Messages
305
Reaction score
0
White light (ranging in wavelengths from 380 to 750 nm) is incident on a metal with work function Wo = 2.46 eV.
(a) What is the maximum kinetic energy of the electrons emitted from the surface?

KEmax = eV


E = hf = hc/lamda.

E = (6.626*10^-34)(3*10^8) / (750*10^-9) = 2.6504E-19

I know to get KEmax i need to do 2.35- something = 0


Thanks
 
Physics news on Phys.org
Note that energy of the photon is 'inversely proportional' to wavelength, and directly proportional to frequency.

The KEmax(photoelectron) = Emax(photon) - Wo
 
Astronuc said:
Note that energy of the photon is 'inversely proportional' to wavelength, and directly proportional to frequency.

The KEmax(photoelectron) = Emax(photon) - Wo
so i found emax which was 2.65E-19 right? so wat i would do is 2.65E-19 - 2.35?
 
Your E_max value is the energy contained within the photon of light.
For every photon absorbed (E_max worth of energy), some amount of that energy is spent removing the electron from the metal and the rest goes into the KE of the electron.

KE_max_electron = E_max - W_o
You are given a value for W_o in terms of electronvolts (a unit of energy) and you have previously calculated the E_max value, so you should be able to calculate from here the max KE value of the electron.

1 eV = 1.602176462 E-19 Joules
 

Similar threads

  • · Replies 25 ·
Replies
25
Views
5K
  • · Replies 35 ·
2
Replies
35
Views
4K
  • · Replies 8 ·
Replies
8
Views
3K
Replies
4
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 5 ·
Replies
5
Views
3K
Replies
3
Views
2K
Replies
6
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 1 ·
Replies
1
Views
3K