# Homework Help: Help needed: Charge on 2 spherical conductors connected with a cylindrical conducor

1. Nov 21, 2008

### bobmerhebi

1. The problem statement, all variables and given/known data

2 conducting spheres with radii 2 & 3m are connected with a conducting rod of thickness 0.1m & lenght 0.5m. 500C charge is put on the 2m radius sphere.
Find the amount of charge on each sphere & on the rod.

2. Relevant equations

3. The attempt at a solution

By conservation of charges: Q1 + Q2 + Q3 = 500 ... (1); Q1 of rod & Q2 & Q3 of 2m & 3m radii spheres respectively.

As charges are uniformly distributed we have: $$\sigma$$1 = $$\sigma$$2 = $$\sigma$$3

so Q1/A1 = Q2/A2 = Q3/A3 ... (2)

here i got stuck & don;t know how to continue. i know that i need to find 3 equations with 3 unkowns & solve the system, but im not seeing these equation except for (1) & probably i have to use parts of (2).

could someone help plz. thx

2. Nov 22, 2008

### fikus

Re: help needed: Charge on 2 spherical conductors connected with a cylindrical conduc

you have three equations, (1) and two equations in (2). Q_1/A_1 = Q_2/A_2 and Q_2/A_2 = Q_3/A_3.

3. Nov 22, 2008

### bobmerhebi

Re: help needed: Charge on 2 spherical conductors connected with a cylindrical conduc

thx 4 the help

4. Nov 22, 2008

### naresh

Re: help needed: Charge on 2 spherical conductors connected with a cylindrical conduc

Can you justify this?

5. Nov 23, 2008

### bobmerhebi

Re: help needed: Charge on 2 spherical conductors connected with a cylindrical conduc

coz charges on conductors tend to uniformly distribute them selves. isn't it?