An old-style TV set places 20 kV across two plates of a parallel plate capacitor
ID: 2120058 • Letter: A
Question
An old-style TV set places 20 kV across two plates of a parallel plate capacitor. An electron is released very close to one plate, and it accelerates rapidly towards the second plate which has a hole drilled through it. The electron exits the hole and hits a phosphor on the glass screen where the picture appears and the phosphor glows.
A.If the plate where the electron is released is 0 V, what is the voltage of the plate with the hole in it? (V)
B.What is the speed of the electron when it exits the hole in the plate? (m/s)
Explanation / Answer
a. voltage of the hole should be 20kv
b.speed of the electron when it exit the hole is v = at =
where a = qE/m = qV/ (md) m is mass, V is potentia difference = 20kv and d is distance between two plates