# Why is the e field 0?

1. Sep 6, 2011

### charlies1902

1. The problem statement, all variables and given/known data
An inner conductor has radius 1.5cm and linear charge density 6 nC/m and the outer conduct has no net charge. The outer conductor has radius 4.5cm and 6.5cm.
Find the e field for all values of R where R is the perpendicular distance from the common axis of cylindrical system.

In the book they had that E=0 for r<1.5cm.
Why is that, shouldn't E=0 if it was a hollow conductor. In this case the book is drawing the conductor has a solid cylinder, not a hollow one. The big conductor is hollow with the 2 radius but not he smaller one. Can someone explain this to me.

Edit-I think they assumed the charge would be 0 for r<1.5cm

2. Sep 6, 2011

### Pengwuino

Hmm I think I would need to see a pic to make sure I fully understand what the object is. You should be able to use Gauss for each situation in these types of problems.

3. Sep 6, 2011

### SammyS

Staff Emeritus
If there is a non-zero field within a conducting material, what will happen to the charges which are free to move?

4. Sep 6, 2011

5. Sep 7, 2011

### serverxeon

ask urself what will happen if there is an electric field set up within a conductor. what will happen to the charges?

6. Sep 7, 2011

### ashishsinghal

In a conductor the charge is on the surface. Hence E will be zero