## anonymous 3 years ago is electric field of sphere and disk same?

1. Kainui

What do you mean? They could both have the same strength, but not the same vectors.

2. anonymous

find electric field caused by a sphere of radius R with uniform surface charge density sigma at a point along axis of disk at a distance x from its centre should i follw same method as for a disk?.

3. Kainui

Basically, yes.

4. anonymous

electric field at a distance R by sphere of uniform charge density is if R> radius of sphere $E=\frac{ Q }{ 4 \pi \epsilon R^2 }$ and for R < radius of sphere (A) is $E=\frac{ Q R }{ 4 \pi \epsilon A^3 }$ now if we talk about disc then, lets say at a distance X from the center of disc along the axis of rotation $E=2 \pi \sigma k(1- \frac{ X }{ \sqrt{X^2+R^2} } )$ for X>0, R is radius of disc and for X<R electric field is $E \approx 2 \pi \sigma k$

5. anonymous

now, i hope you can better judge and analyse if its same and at what distance or not :)

6. anonymous

thnx

7. anonymous

:D