Suppose that a=4 cm, b=21 cm, and c=28 cm. Furthermore, suppose that the electric field at a point 11 cm from the center is measured to be 2420 N/C radially inward while the electric field at a point 63 cm from the center is 130 N/C radially outward. Find the charge on the insulating sphere.(adsbygoogle = window.adsbygoogle || []).push({});

I'm sorry I can't post the picture, but it is an insulator with a radius 4 cm, that is inside of another sphere with a radius of 21 cm measured from the center, which is inside of a conductor with a radius of 28 cm measured from the center.

We did part of this problem in class and found that the [tex]Q_e_n_c = E_1 *4\pi* R_g^2 *E_0. [/tex]

I'm pretty sure that E_1 = 2420 N/C and E_0= 8.85 x 10^-12, but I'm a little confused about which radius to use. I thought it would be the radius of the insulator which is .04 m, but this wasn't right. Can someone please help?

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

Dismiss Notice

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!

# Net charge on sphere

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