Question

A small glass bead has been charged to + 20 nC . What is the the acceleration of a proton that is 4.0 cm from the center of the bead? Input positive value if the acceleration is derected toward the bead and negative if it is directed away from the bead. What is the the acceleration of an electron that is 2.5 cm from the center of the bead? Input positive value if the acceleration is derected toward the bead and negative if it is directed away from the bead.

Answer 1

a) Force exerted on the electron by the bead is
F = q1*q2 / (4pi*Eo*r^2)
F = 20*10^-9C * 1.6*10^-19C / (4pi*8.85*10^-12*0.04^2) N = 1.8*10^-14 N

Acceleration of electron is a = F/m = 1.8*10^-14 / 9.11*10^-31 m/s^2
a = 1.97 *10^16 m/s^2

b)  Force exerted on the electron by the bead is
F = q1*q2 / (4pi*Eo*r^2)
F = 20*10^-9C * 1.6*10^-19C / (4pi*8.85*10^-12*0.025^2) N = 4.6*10^-14 N

Acceleration of electron is a = F/m = 4.6*10^-14 / 9.11*10^-31 m/s^2
a = 5.05 *10^16 m/s^2