7.8 understand that ionising radiations can be detected using a photographic film or a Geiger-Muller detector
Photographic film is a traditional way to detect ionising radiation. Ionising radiations imprints photographic plates.
Geiger Muller tube is used to measure the level of radiation. It is a glass tube with an electrically conducting coating on the inside surface. The tube has a thin window made of mica. The tube contains low pressured gases. In the middle of the tube, there is an electrode which is connected to a high voltage supply via a resistor. When ionising radiation enters the tube through the glass, it causes the low pressured gas to form ions. As ions are charged particle they allow to flow a pulse of current in the electrode which is detected by an electronic circuit.