# Photoelectric effect and cutoff frequency

## Homework Statement

I was just wondering that when I have a graph of the Stopping Potential versus Frequency of the light. How can I find the value for the cutoff frequency?
Wavelength Vo
160 nm 2.99 V
53 nm 19.18 V
80 nm 11.00 V
160 nm 2.93 V
187 nm 1.92 V

## The Attempt at a Solution

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rock.freak667
Homework Helper
Write down the equation for the photoelectric effect and then use the fact that the stopping potential is the work done in stopping the electrons from having any kinetic energy.

well i found the theoretical value of the slope: 4.14125 X 10^-15 Js/C and the actual value of the slope: 3.9512 X 10^15 J s/C but don't know how to use them to find the answer

As rockfreak advised write down the equation.Next rearrange it to make V the subject of the equation and then compare what you have to the equation of a straight line.By comparison you should be able to identify what the gradient of the graph represent and what the intercepts on the y and the x axis represent.

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As rockfreak advised write down the equation.Next rearrange it to make V the subject of the equation and then compare what you have to the equation of a straight line.By comparison you should be able to identify what the gradient of the graph represent and what the intercepts on the y and the x axis represent.
does the y intercept of the graph represent the work function?

Did you plot V on the y axis?If so the intercept has the units of volts ie joules per coulomb.The work function has the units of Joules so what could the intercept represent?Also, look at the intercept on the x axis.