Question

Find the mean free path of an electron travelling at a speed of 18m/s in 2 seconds.

(a) 9

(b) 36

(c) 0.11

(d) 4.5

This question was posed to me by my school teacher while I was bunking the class.

This key question is from Dielectrics topic in portion Electric Fields in Material Space of Electromagnetic Theory

Answer 1

Right option is (b) 36

Best explanation: The mean free path is defined as the average distance travelled by an electron before collision takes place. It is given by, d = v x τc, where v is the velocity and τc is the collision time. Thus d = 18 x 2 = 36m.