- #1
Liquidxlax
- 322
- 0
Homework Statement
You don't really need to read the top paragraph.
A Geiger counter is used to detect ionizing radiation. The detector consists of a thin wire that is surrounded by a concentric circular conducting cylinder. A high voltage is applied to the wire so that it has a positive charge and the surrounding cylinder has the same amount of negative charge. This establishes a very strong electric field inside the cylinder. A low pressure inert gas is inside the cylinder, so that when radiation enters the cylinder it ionizes a few of the gas atoms, and the resulting free electrons are attracted to the positive wire. The e field is so strong as to enable the gas atoms between collisions to gain enough energy to ionize these atoms as well, creating more free electrons, and a chain reaction ensues. An "avalanche" of electrons reaches the wire that is collected by the wire and generates a signal.
Suppose the radius of the central wire is 25x10^(-6)m, the cylinder has a 0.014m radius and the cylinder length is 0.16m. The electric field magnitude at the cylinder wall is 2.9x10^(4) N/C. What is the amount of charge and it's polarity on the central wire?
Homework Equations
Er = (4pikQ)/(2pirL) cylinder charge distribution
rho = Q/L
surface area cylinder 2piRL
The Attempt at a Solution
E = kQ/2piRL + KQ/2pirL
yeah... I'm not sure about this one
can't get the latex or w.e to work hold on