An electron is accelerated through a pair of parallel plates with a voltage di?e

ID: 3901282 • Letter: A

Question

An electron is accelerated through a pair of parallel plates with a voltage

di?erence of 100V. After leaving the plates it enters a region with a uniform

magnetic ?eld of .1 T that is perpendicular to the direction of the electrons

motion.

2.a What is the speed of the electron after it leaves the plates?

2.b What is the radius of the curve of the electron after it enters the

magnetic ?eld.

2.c How much work does the magnetic ?eld do in making the electron

move in a circle?

What potential across the plates would be needed to double the radius of the circle?

2. a. 1/2 mv^2 = e V

0.5*9.11E-31*v^2 = 1.6E-19*100

v=5.93E6 m/s

b) q v B = mv^2/r

r = mv/(q B) = 9.11E31*5.93E6/(1.6E-19*0.1)=3.38E-4 m

c) W magnetic = 0

d) need to double v to double r

to double v we need to 4 times V

so 400 V

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.