Can someone please explain how geiger-muller works I'm devastated

The ionising effect of radiation is used in the Geiger-Muller (GM) tube as a means of detecting the radiation. The GM tube is a hollow cylinder filled with a gas at low pressure. ... When alpha, beta or gamma radiation enters the tube it produces ions in the gas. The ions created in the gas enable the tube to conduct.

Explanation:

The Geiger–Müller tube is filled with an inert gas such as helium, neon, or argon at low pressure, to which a high voltage is applied. The tube briefly conducts electrical charge when a particle or photon of incident radiation makes the gas conductive by ionization.

if you already have the answer to (a), then just work out how many periods there are in 1 minute, and that's the answer to (c).

a.) is the correct answer.

explanation: