La bactivities and questions Run 1: Sodium In this activity, Sodium is selected as the target surface. Recall that in theory, 8?8?8?8?6? = E? - 6?AWhere BE is the binding energy of the electron to the target material. For each particular radiation wavelength (frequency), you measure a stopping potential, V's, and thus can calculate the maximum kinetic energy of the ejected electrons using B ?8 = ?8?87578387+ 8? = 1.60 x 10-19 C. 1. After you open the simulation, move the mouse to the upper left corner of the application window, dick "options", and check off "control photon number instead of intensity". 2. At the default starting point, where the DC voltage is zero and the wavelength of the radiation is 400nm, ind ease number of photons to 100. 3. Immediately you should see electrons ejected from the target surface and the current meter shows a nonzero value. Move the switch icon on the battery left or right to see how the electronsrespond to the applied voltage. When a positive voltage is applied they accelerate to the right, and when a negative voltage is applied they slow down or even turn around and move back to the metal surface. Practice finding the stopping potential, Vs, by adjusting the voltage control or typing in the value. Hint: you are looking for a negative voltage at which the current switches from a small but nonzero value to zero. If done carefully, Vs can be measured to the second decimal place