# Electric Field

## Homework Statement

If the electric field at a point in space has a magnitude of 300 volts/meter, about how far apart are the equipotential surfaces that differ by 10 volts?

well, i think that they are 30 meters apart. All I did was

300 volts/meter/10 volts since that will cancel the volts out i believe and leaving me with 300 meter/10 which give 30 meters.

I dont understand this question since my professor decided to skip this portion of the chapter and expect us to know it.

Any help on understanding would be great.

berkeman
Mentor
I think your answer and your intuition are correct. They certainly are for parallel plate capacitors. And I think they probably apply here for this spherical situation as well.

hage567
Homework Helper

300 volts/meter/10 volts since that will cancel the volts out i believe and leaving me with 300 meter/10 which give 30 meters.

EDIT: hage567 beat me to it.

I just realize that. Now i have a problem on doing conversion with this. Can any of you guys give me some pointer on how to understand this since I quiet dont understand it.

I know there is this formula E = Kq/r^2 but I am not sure if that is what i have to use to figure this out.

I have also seek my lab TA for help on this and I still haven't even gotten a response and its been like 2 days.

Last edited:
Okay, i got some help but can anyone double check this to see if its the correct way,

10 volts/ 300vots/meter = .033 meter

nrqed
Homework Helper
Gold Member
Okay, i got some help but can anyone double check this to see if its the correct way,

10 volts/ 300vots/meter = .033 meter

Yes, that is right (assuming a uniform E field...that assumption is needed to answer the question). It's clear that this is correct since if the potential changes by 300 volts over a distance of 1.00 meter, it must take only 1.00 meter/30 to get a change of 10 volts.

Sweet, thanks for checking it.

thanks to everyone who posted here.