Register to reply

Need help with electric field questions thx

by ELHEK
Tags: electric, field
Share this thread:
ELHEK
#1
Aug8-06, 07:52 AM
P: 8
Hey everyone! I'm currently knew to the site, i found it searching for help on electric field problems n such. If anyone could help me that would be great! thx again

1) A proton orbits a long chared wire, making 1.0x10^6 revolutions per second. The radius of the orbit is 1.0cm. What is the wire's linear charge density?

2) Show that the on axis electic field of a ring of charge has the expected behaviour when z<<R and when z>>R.

The answer to the first questions is -2.29nC/m, but im clueless about how to go about it, i've also tried applying circular kinematics but have not been successful. The second question i am absolutly dumbfounded by. Thx again anyone who helps!
Phys.Org News Partner Science news on Phys.org
World's largest solar boat on Greek prehistoric mission
Google searches hold key to future market crashes
Mineral magic? Common mineral capable of making and breaking bonds
Astronuc
#2
Aug8-06, 11:08 AM
Admin
Astronuc's Avatar
P: 21,827
Quote Quote by ELHEK
1) A proton orbits a long chared wire, making 1.0x10^6 revolutions per second. The radius of the orbit is 1.0cm. What is the wire's linear charge density?

2) Show that the on axis electic field of a ring of charge has the expected behaviour when z<<R and when z>>R.

. . . i've also tried applying circular kinematics but have not been successful.
What has one tried with respect to circular kinematics?

When a charge moves in a circular trajectory, the centripetal force must balance the electric force, and the electric force must be 'attractive' if the moving charge moves around the source of the electric field. In the case of a line charge, the charge must be negative in order to be attractive to a positively charge proton.

F = q E = centripetal force. I leave this to the student to complete.

The second questions makes no sense. There has to be more to it, as in a description of the expected behavior.

This might help -
http://hyperphysics.phy-astr.gsu.edu...ic/potlin.html
ELHEK
#3
Aug9-06, 03:36 AM
P: 8
k thx, just checking im on the right track, i found the force by F=(mv^2)r.
then by using E = F/q (q = 1.6x10^-19), but this is where im stuck any more pointers please? thx again


Register to reply

Related Discussions
Need help on Electric Field Questions Introductory Physics Homework 1
Electric Field questions. Introductory Physics Homework 1
Electric field/equipotential field questions Introductory Physics Homework 4
Electric field questions Introductory Physics Homework 0
Electric Field/Magnetic Field Questions Introductory Physics Homework 1