Question

Suppose a particle of ionizing radiation deposits 1.0 MeV in the gas of a Geiger tube, all of which goes to creating ion pairs. Each ion pair requires 30.0 eV of energy.

(a) The applied voltage sweeps the ions out of the gas in 1.00μs. What is the current?

a) 3.0 mA
b) 30.0 mA
c) 300.0 mA
d) 3.0 A

Answer 1

To find the current, divide the number of ion pairs by the time it takes to sweep the ions out of the gas. In this case, the number of ion pairs is 3.3 x 10^4 and the time is 1.00 us.

Step-by-step explanation:

To find the current, we first need to determine the number of ion pairs created by the particle. Since each ion pair requires 30.0 eV of energy, the number of ion pairs created is equal to the total energy deposited (1.0 MeV) divided by the energy required for each ion pair (30.0 eV).

Number of ion pairs = (1.0 MeV) / (30.0 eV) = (1.0 × 106 eV) / (30.0 eV) = 3.3 × 104 ion pairs

Now, to find the current, we divide the number of ion pairs by the time it takes to sweep the ions out of the gas (1.00 us):

Current = Number of ion pairs / Time = (3.3 × 104 ion pairs) / (1.00 µs) = 3.3 × 104 ion pairs / µs