Hello everyone, I managed to get Parts (a) and (b) of this problem but can't get the last for some reason. A metal sphere of radius 15cm has a net charge of 2.0E-8C. THe question is, at what distance from the sphere's surface has the electric potential decrased by 700V? Well i found the electric field to be 7992.7 N/C at the sphere's surface. I also found If V = 0 at infinity, what is the electric potenital at the sphere's surface? I used Vsurface = kQ/(r). to find Vsurface being equal to 1198.9V. But I can't figure this part out. I pluged in 700V for Vsurface and solved for r, and got .2569m. r = kQ/Vsurface; This was wrong So i tried, [tex]Vf - Vi = -\int E.ds [/tex] Plugged 700V for Vf-Vi and solved for ds, because i know E from above and I know Vf-Vi, and i got .584m, also wrong any ideas? thanks(adsbygoogle = window.adsbygoogle || []).push({});

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# At what distance has spheres decreased Electric potential by 700V?

**Physics Forums | Science Articles, Homework Help, Discussion**