An investigator measures the ambient background radiation rate in a laboratory to be 15 counts per minute. They then set up an alpha radiation source directed towards a Geiger-Müller detector. A single sheet of standard paper is placed directly between the alpha source and the detector.
Estimate the count rate now recorded by the detector.
81 exam-style questions on Edexcel GCSE Physics 6.1 Atomic structure and isotopes, covering 6.1.1 Structure of the atom, 6.1.2 Isotopes: atomic and mass number, 6.1.3 Sub-atomic particles: masses and charges, and 6.1.4 Electron orbits and energy changes. Each one has a worked solution and a mark scheme showing where the marks go.