Background The photoelectric effect is the emission of electrons from a material when light is shone upon the material. The energy of a photon can be given by the equation where v is the frequency of the photon and h is a constant known as Planck's constant. The frequency of the photon is related to the wavelength of the light through the equation :uln where c is the speed of light. The energy of the photon can be related to the energy of the ejected electron through the relation E=KE+ (1: and using the first equation, this can be rewritten as KE=hv gb where KE is the kinetic energy of the ejected electron and d) is the energy that keeps the electron bound to the nucleus, which is known as the work function. The work function is specic to the material the electrons are ejected from. Part 1: The Nature of Light 1. Navigate to htt s: het.co|orado.edu sims cheer ' hotoelectric latest hotoelectric.htm|?simu|ation= h otoelectric 2. Adjust the wavelength of the light to 550 nm. This can be done by sliding the bar or by clicking the value of the wavelength and entering the value. The same can be done for intensity of the light. Is there any intensity for which electrons are emitted? 3. With the intensity set to 50%, nd the value of the wavelength at which electrons are rst emitted from the material. Record this value below. Increase the intensity of the light to 100%. Does the velocity, and therefore the kinetic energy of the ejected electrons increase? Does this mean that light is behaving like a particle or a wave? Part 2: Determining Planck's Constant l. The kinetic energy of the electrons can be measured by setting the \"stopping potential\4. Create a plot of the kinetic energy vs the frequency, and insert it below. Remember to properly label axes and the title. Be sure to insert a line of best t and the equation for the line of best fit. 5. By comparing your equation of the line of best t to the equation for the kinetic energy of the ejected electrons, identify which quantities your slope and y intercept correspond to. 6. Calculate the percent difference between the value of your slope and the accepted value of Planck's constant, 4.136 x 10A-15 eV/Hz, and the percent difference between your y intercept and the accepted value of the work function of sodium, 2.28 eV. Part 3: Material Identication 1. Repeat the experiment of Part 2, but with the material \"?????\". Complete the table below, and make a plot of kinetic energy vs frequency, and insert it on the next page. From the value of the work function from your equation of best fit, identify the material from the table at http://hyperphysics.phy-astr.gsu.edu/hbase/Tables/photoelec.html. Calculate a percent difference. A (nm) v (Hz) Vstop (eV) KE (eV) 300 290 280 270 260 250 Questions 1. Calculate the threshold wavelength of a incident photon needed in order to eject an electron from a copper plate ($ = 4.7 eV). Show your work.2. What is the velocity of an electron ejected from a copper plate from a photon whose wavelength is 230 nm in a potential of 0.0V? Use the value of Planck's constant h = 6.63 x IDA-34 I s, and convert the work function of copper to joules. Show your work 3. The momentum of a photon is given through the equation: _ h P i where h is Planck's constant and A is the photons wavelength. Using the velocity you calculated in question 2, nd whether momentum is conserved during the collision between the photon and the electron. 1f momentum is not conserved, give a possible explanation for the missing momentum