- #1
pyroknife
- 613
- 3
A solid sphere of +20C with radius a=1m. A conducting spherical shell of -30C with radius b=2m and c=3m is concentric with the solid sphere.
1. Find the inner and outer surface charge of the conducting spherical shell.
My attempt: I just eyeballed it and said -20C is on the inner shell b/c the +20C is attracting it and the rest -10C is on the outer shell.
2. Graph V vs r(the radius from the center).
My attempt: I calculated V at each of the regions.
region 1: r<1 the V due to a solid sphere is (kQ/2R)(3-r^2/R^2)=30k-10r^2
region 2: 1<r<2 V=kQ/r=20k/r
region 3: 2<r<3 r=0
region 4: r>3 V=-10k/r
I attached my graph which i drew on paint.
you can't see 0 between 2&3 but it's there.
1. Find the inner and outer surface charge of the conducting spherical shell.
My attempt: I just eyeballed it and said -20C is on the inner shell b/c the +20C is attracting it and the rest -10C is on the outer shell.
2. Graph V vs r(the radius from the center).
My attempt: I calculated V at each of the regions.
region 1: r<1 the V due to a solid sphere is (kQ/2R)(3-r^2/R^2)=30k-10r^2
region 2: 1<r<2 V=kQ/r=20k/r
region 3: 2<r<3 r=0
region 4: r>3 V=-10k/r
I attached my graph which i drew on paint.
you can't see 0 between 2&3 but it's there.