Use a plastic ruler to push the sphere toward the positive plate of the capacitor and touch the positive plate. Let it swing freely. a. Leaving the power supply turned on, observe the sphere and determine its period of oscillation.

a.What would you expect to happen if the voltage is reduced? What factors affect its period? How could you “tune” it to make T = 1 second?

b. Restore the voltage to 2 kV while the sphere is still oscillating, and shut off the voltage. Observe what happens. Explain the process taking place that causes the “clock” to stop.

c. With the power supply off, discharge the sphere completely (with a wire connected to ground) and increase the plate voltage to 2 kV. Use a plastic ruler to move the sphere to touch the positive plate but don’t let it swing. Let it hang between the plates in a charged condition and observe what happens. Lab 2 - 4 If there is a charged body Q in an electric field E, shouldn’t a force F = Q E be exerted on the sphere? Why does it not deflect or start to oscillate from rest?

(To answer these questions you should know the theory behind the simple pendulum. You should be able to draw free body diagram for a pendulum and try to derive the equation for its period. See if things change or not. 

 

o 100 100 MQ w Power Supply Digital Voltmeter