In a packaging plant, a gamma radiation source and a Geiger-Müller (GM) tube detector are used to monitor the density of a liquid detergent flowing through a delivery pipe. The nominal (ideal) detected count rate is 560 counts per minute560\text{ counts per minute}560 counts per minute.
If the density of the detergent drops, the detected count rate increases. The flow valve must be shut off if the count rate increases by 7.5%.
Calculate the maximum count rate that is allowed before the valve must be shut off.
90 exam-style questions on Edexcel GCSE Physics 6.3 Nuclear equations and decay, covering 6.3.1 Beta-minus and beta-plus decay, 6.3.2 Effects of decay on the nucleus, and 6.3.3 Balancing nuclear equations. Each one has a worked solution and a mark scheme showing where the marks go.