A Geiger counter is a device used to detect ionizing radiation (radiation which is powerful enough to ionize an atom). The counter consists of a thin positively charged wire surrounded by a concentric, conducting cylinder with an equal negative charge. The cylinder contains a low pressure inert gas. When a particle of radiation enters the device through the cylinder walls, it ionizes a few of the gas atoms. The resulting free electrons a drawn towards the wire, ionizing other atoms on the way. This "avalanche" of electrons is collected on the wire where it causes a detectable current.
A particular Gieger counter has a metal cylinder with an inner diameter of 2.1 cm along whose axis is stretched a wire with 36 N of tension. The potential difference between the wire and the cylinder is 820 volts. The wire has a length of 10 cm and an outer diameter of 1.1 X 10-4 cm.
a) What is the electric field at the surface of the wire?
Ewire= V/m
You can use Guass' Law to find the electric field of an object which is cylindically symetric. Use the intergral relationship between the E field and the potential difference to find the constants involved.
b) What is the electric field at the inner surface of the cylinder?