The electric field strength is 2.40×10 4 N/C inside a parallel-plate capacitor w
ID: 1398858 • Letter: T
Question
The electric field strength is 2.40×104 N/C inside a parallel-plate capacitor with a 1.20 mm spacing. An electron is released from rest at the negative plate.
1) What is the electron's speed when it reaches the positive plate?
A thin, horizontal, 14-cm-diameter copper plate is charged to 3.0 nC . Assume that the electrons are uniformly distributed on the surface
1) What is the strength of the electric field 0.1 mm above the center of the top surface of the plate?
2) What is the strength of the electric field 0.1 mm below the center of the bottom surface of the plate?
Explanation / Answer
By F = qE
=>m x a = qE
=>a = qE/m
=>a = [1.6 x 10^-19 x 2.10 x 10^4]/[9.11 x 10^-31]
=>a = 3.69 x 10^15 m/s^2
=>By v^2 = u^2 + 2as
=>v^2 = 0 + 2 x 3.69 x 10^15 x 1.2 x 10^-3
=>v =[4.43 x 10^12]
=>v = 2.10 x 10^6 m/s