In a photoelectric experiment on the metal copper, the following values of the stopping potential V0 were obtained at different wavelengths (lambda) of the incident ultraviolet light.
| λ(nm) |
200 |
210 |
220 |
230 |
240 |
| Vo(Volts) |
1.27 |
0.98 |
0.71 |
0.46 |
0.24 |
a. Use a graphical method to determine a value for the work function of copper.
b. Find the maximum velocity of an ejected electron if the copper surface is illuminated by radiation with a wavelength of 122nm, the longest wavelength line of the Lyman series (transitions to n=1) of hydrogen.