Modern PhysicsModern Physics(PC300)(PC300)

Class #8: Quantum Mechanics BornClass #8: Quantum Mechanics Born

Test Test AssessmentAssessment

Photoelectric EffectPhotoelectric Effect

0max

2

2

1eVmv

+ -

Photoelectric Effect: IntensityPhotoelectric Effect: Intensity

Photoelectric Effect: FrequencyPhotoelectric Effect: Frequency

Maximum KE does not depend on intensity1902: Lenard -

1905 Lenard - Nobel Prize

1905: Photoelectric Effect: 1905: Photoelectric Effect: SolutionSolution

Classical electromagnetic theory has problems explaining the independence of Kmax and light intensity, the linear dependence of Kmax on light frequency and the instantaneous (10-9s) response of the photocurrent.

1921 Einstein - Nobel Prize

Einstein - Light composed of irreducible "grains" - quanta (energy packets).

1905 What a year for Einsteinhttp://www.aip.org/history/einstein/chron-1905.htm

Photoelectric Effect: Work Photoelectric Effect: Work FunctionsFunctions

hfeVmv Smax

2

2

1

(Kmax)

Various Work FunctionsVarious Work Functions

1923 Millikan - Nobel Prize

http://www.youtube.com/watch?v=m55kgyApYrY

Problem Set for WednesdayProblem Set for Wednesday

To answer the first two questions you will first need to do a Simulation.To answer the first two questions you will first need to do a Simulation.Run the Photoelectric Effect program by following the steps below.Run the Photoelectric Effect program by following the steps below.

  

P:\Academic\White\PC301 Modern Physics 2013\Programs\Photoelectric\P:\Academic\White\PC301 Modern Physics 2013\Programs\Photoelectric\Photoelectric_enPhotoelectric_en

  

Take data to answer the following question. Take data to answer the following question.

1. Using five different wavelengths striking Sodium, calculate the ratio h/e. (Hint, make a 1. Using five different wavelengths striking Sodium, calculate the ratio h/e. (Hint, make a graph in Excel of the Stopping Potential vs. frequency. Include this graph, with a graph in Excel of the Stopping Potential vs. frequency. Include this graph, with a trendline, in your homework solution. And remember, that all graphs need labels, a title, trendline, in your homework solution. And remember, that all graphs need labels, a title, and a short caption…)and a short caption…)

  

2. Find the Workfunction for each of the six elements (most of which are metals…2. Find the Workfunction for each of the six elements (most of which are metals…including the unknown) used in the simulation. Make a simple chart of your findings. including the unknown) used in the simulation. Make a simple chart of your findings. Write a few sentences that clearly describe what procedure you followed and how you Write a few sentences that clearly describe what procedure you followed and how you arrived at these conclusions.arrived at these conclusions.

  

Sim #4: Photoelectric Effect Sim #4: Photoelectric Effect

P-Drive\White\Modern Physics\Programs\Petutor\CTWINXClick on Photo15.ctb then hit OK

Lab 6 – Photoelectric EffectLab 6 – Photoelectric Effect

X Ray ProductionX Ray Production

1901 Roentgen - Nobel Prize

EM Spectrum: X-RaysEM Spectrum: X-Rays

(Duane-Hunt Rule)0

min

1

Ve

hc

Quantum Homework QuestionsQuantum Homework Questions

Some Simulation Some Simulation Questions and an Questions and an Electron Gun questionElectron Gun question

Also…Also…

Thornton and Rex!Thornton and Rex!

Due Wed normal timeDue Wed normal time"Yeah, well I got mine first

1897 - J.J.Thompson1897 - J.J.Thompson

1906 - Nobel Prize

X Ray ProductionX Ray Production

Measuring charge/mass (e/m)Measuring charge/mass (e/m)

Electron beam Cathode Ray

Cathode Ray Tube

2 2

2Ve

m R B

Derive in lab

Lab ? - e/m setupLab ? - e/m setup

1909 - Robert Millikan 1909 - Robert Millikan Precise Measurement of ePrecise Measurement of e

Oil Drop ExperimentOil Drop Experiment