Question

A small piece of dust of mass m = 4.1 µg travels through an electric air cleaner in which the electric field is 466 N/C. The electric force on the dust particle is equal to the weight of the particle.
(a) What is the charge on the dust particle?
C

(b) If this charge is provided by an excess of electrons, how many electrons does that correspond to?
electrons

Answer 1

Answer:

Explanation:

mass, m = 4.1 x 10^-6 g

Electric field, E = 466 N/C

Electric force = weight

(a) Electric force = q x E = m x g

where, q be the charge on the dust particle.

q x 466 = 4.1 x 10^-6 x 9.8

q = 8.62 x 10^-8 C

(b) Number of electron  = charge / charge of one electron

n = 8.62 x 10^-8 / (1.6 x 10^-19)

n = 5.4 x 10^11