# Capacitor and Charges?

1. A conducting solid sphere of radius R1 carries charge +Q1, It is surrounded by a concentric spherical conducting shell of radius R2 with charge +Q2.

Find the potential at the shell surface taking V=0 at infinity.

What is the electric field inside the solid sphere?

2. Two capacitors are connected in series and the combination is charged to 100 V. If the voltage across C1 is 20 V and the voltage across C2 is 80 V, how do their capacitances compare?

### 1 Answer

- NCSLv 72 months agoFavorite Answer
1. I would construe "at the shell surface" to include the shell's charge; then the potential at the surface is

Vsur = k*(Q1 + Q2) / R2

where k = 8.99e9 N·m²/C²

The electric field within any conductor is zero.

2. Since the charge must be the same on both capacitors, we know that

V1*C1 = V2*C2, so

V1 / V2 = C2 / C1 = 80V / 20V = 4:1

Hope this helps!

Source(s): Please revisit this working: https://answers.yahoo.com/question/index?qid=20200... TIA