Register to reply

Electric Potential in Insulated U-Tube

by PK_Kermit
Tags: electric, insulated, potential, utube
Share this thread:
PK_Kermit
#1
Mar7-06, 10:35 AM
P: 1
Hey, I have this question, and I'm having quite a bit of difficulty figuring it out.

"An insulating rod is bent into a semicircular arc of radius a, and a total electric charge Q is distributed uniformly along the rod. Calculate the potential at the center of curvature of the arc if the potential is assumed to be zero at infinity."

Which i see to be as so:

..........|.........|.................................................. .....
..........|.........|.................................................. .......
..........|....o...|.......<- the 'o' represents the center of curvature of
...........\...... /............................................the arc....
.............\.../......<-- this part is round.........................
...............u....................................................... ......

There is a similar question in my textbook, where tehy work out the potential at a point from a ring of charge. they use the equasion:

V= (1/4[pi]E0) [integral] dq/r

[where dq would be infinitismal elements of charge about the ring]

for the ring, the r distance is always the same; so they remove r and integrate dq, to end with:

V= (1/4[pi]E0) ( Q / r )

now, my question is the U tube. I figure, since under the center of curvature lies a semicircle, maybe you could take half the potential found from the previous equasion; i.e., for the curvature part, you could use:

0.5(1/4[pi]E0)( Q / r )

but, there is nothing in my textbook to say what I would do in terms of the extending arms of the U tube; as well, the question doesn't say anything about the length of the arms.

what is the significance of defining V to be zero at infinity, and where should I go from here?

Thanks,
PK_Kermit
Phys.Org News Partner Science news on Phys.org
Experts defend operational earthquake forecasting, counter critiques
EU urged to convert TV frequencies to mobile broadband
Sierra Nevada freshwater runoff could drop 26 percent by 2100

Register to reply

Related Discussions
Electric Potential Energy and Electric Potential Difference Introductory Physics Homework 2
Electric field in tube... Introductory Physics Homework 5
Electric potential and electric potential energy question... Introductory Physics Homework 1
Electric Potential/Electric Potential Energy question... Introductory Physics Homework 3
Electric field and a tv tube Introductory Physics Homework 3