A radiation protection officer uses a portable scintillation counter to monitor the ambient background radiation rate in an analytical chemistry laboratory. The officer records the count rate over four separate ten-second intervals, obtaining the data shown in the table below.
| 1st count rate | 2nd count rate | 3rd count rate | 4th count rate | |
|---|---|---|---|---|
| Count rate (cps) | 26 | 31 | 25 | 30 |
Calculate the mean background count rate, in cps, from these four measurements.
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.