1. The y-axis of the graph shows the maximum kinetic energy of the electrons, which is numerically equal to the stopping potential (the minimum battery voltage required to reduce the current to zero). Why are these values numerically equal? (Note the units used for KEmax.)
2. What does the x-intercept of the graph represent?
3. If light in just the visible spectrum was used to illuminate the plates, from which materials (aluminum, silver, or sodium) would electrons be ejected?
4. Does the number of points on your graph affect the accuracy of the values of Planck’s constant and work function you determined using the simulation?
5. The method suggested to carry out the experiment, recording the minimum voltage required to reduce the current to zero, introduces a small systematic error by consistently obtaining values for KEmax that are close to, but generally a little larger than, the actual KEmax values. For instance, if KEmax were actually 4.14 volts, you would record it as 4.2 volts because of the limitations of the simulation. Is this systematic error likely to have more impact on the slope of the graph or on the y-intercept? How does the systematic error affect the work function determined from your graph, for instance?
6. Can you find a slightly more accurate method for recording points on the graph, within the current limits of the simulation, that would minimize the systematic error?