Graph

Using one sheet of graph only but three separate graphs, one for each metal, and with each cathode metal $($cesium$,$ potassium and sodium$)$ represented by a separately labelled line on graph. the $E_{\text{k}\text{m}\text{a}\text{x}}(eV)$ versus frequency of radiant light $($frequency is the manipulated variable$).$ Make sure you have negative values on your vertical axis, similar to the graph on the computer screen. Label both axes and provide a title as well as a legend to explain your color code.

Calculations:

Rearrange the $E_{\text{k}\text{m}\text{a}\text{x}}$ formula to isolate Planck's Constant. Calculate the value for $\text{'}$ h $\text{'}$ in each row $($where possible$)$ and take an average. Calculate the percentage error of your estimate $($use $6\mathrm{.}63$ x ${10}^{-34}Js$ as the actual value$).($Note: Since $E_{\text{k}\text{m}\text{a}\text{x}}$ is zero for some frequency values, then an $\text{'}$ h $\text{'}$ value is not possible.$)$

Calculate the slope of each graph, making sure to include units, and record these values below. In addition, be sure to label which slope is for which metal. What does this slope represent?

Show the comparison between your value$($s$)$ for the work function from your graph versus the given work function in the table.

$\backslash$table$[[,"$h$"$ from graph $($Js$),"$h$"$ from table $($Js$)],[$Cesium$,,],[$Potassium$,,],[$Sodium$,,]]$

Questions:

Explain what the difference is between intensity and frequency of the incident light.

What do the negative values of the y$-$intercepts of the graphs represent? Why are they negative?

Suggest a reason$($s$)$ why every metal has a different work function and therefore would re

Problem: To confirm the value of Planck's constant using an applet which simulates the photoelectric effect.

Materials:

Calculator

Graph paper

Straight edge

Pencil

Photoelectric Effect applet

Complete the given table for each cathode type and necessary graphs, calculations and questions.

Note: When there is no photoelectric current, record the $E_{k\text{m}\text{a}\text{x}}$ as $0eV.$

$E_{\text{k}\text{m}\text{a}\text{x}}=q{V}_{\text{s}\text{t}\text{o}\text{p}},E_{\text{k}\text{m}\text{a}\text{x}}=hf-W$

$\backslash$table$[[$Cathode$,$Incident Light,Work Function,$E_{k\text{m}\text{a}\text{x}},\backslash$table$[[$Planck$\text{'}$s$],[$Constant$]]],[$Metal$,$Color,Wavelength $($nM$),\backslash$table$[[$Frequency$],[($Hz$)]],$eV$,$J$,$eV$,$J$,$h$($J$/$Hz$)],[$Cesium$,$Yellow,$578,5\mathrm{.}19{10}^{14},2\mathrm{.}10,3\mathrm{.}36{10}^{-19},,,],[,$Green,$546,,,,,,],[,$Violet,$436,,,,,,],[,$UV $-1,365,,,,,,],[,$UV $-2,254,,,,,,],[$Potassium$,,,,,,,,],[,,,,,,,,],[,,,,,,,,],[,,,,,,,,],[,,,,,,,,],[$Sodium$,,,,,,,,],[,,,,,,,,],[,,,,,,,,],[,,,,,,,,],[,,,,,,,,]]$

Average $"$h$"$quire a different threshold frequency of the incident light for emission of photoelectrons to occur.

Why are the stopping voltages for some wavelengths a value of zero?