Watch the videos below:
5. Calculate the frequency (f) for that wavelength and record it in the table below. Remember that c=?f, where c is the speed of light (3 * 10^8 m/s).
6. Calculate the Energy (E) in joules for that wavelength and record it in the table below. Remember that E = hf, where h the Planck constant (6.6 *10^-34 j*s)
7. Complete the Energy (E) in electro-volt (ev) and record it in the table below.
1 electron-volt (eV) = 1.6 X 10-19 J
8. Repeat the above step for each of the metals under the pull down menu.
Metal Wavelength ?
(nm) Frequency f
(Hz) Energy E
(J) Energy
(eV)
Sodium
Zinc
Copper
Platinum
Calcium
9. The minimum frequency of a photon that can eject an electron from a surface is called the threshold frequency, ft. What is the threshold frequency, ft, for each of the metals?
HINT: revisit instructions 3 & 4.
Metal Threshold Frequency ft (Hz)
Sodium
Zinc
Copper
Platinum
Calcium
10. The minimum amount of energy required for an electron to escape from a metal is called the work function (W) and is given by the equation W = hft. What is the work function for each of the metals in joules and electron-volts? HINT: revisit instructions 3 to 6.
Metal Work Function E
(J) Work Function E
(eV)
Sodium
Zinc
Copper
Platinum
Platinum
Calcium
11. Make the following additional adjustments to the simulation.
• Check the box “current vs. light intensity”.
• Check the box “electron energy vs. frequency”
• Select the Sodium.
• Use violet light (about 400 nm).
• Vary the intensity of the light and observe any changes in the number of ejected electrons.
12. What’s the relationship between the intensity of the incident light and the number of the ejected electrons?
13. What’s the relationship between the intensity of the incident light and the energy of the ejected electrons?
