1500- 1000- 500 time/ minutes (1) Determine the half-life of the radioactive isotope. [2 mks] (ii) Predict the value of the count rate at a time of 6 minutes from the start of the measurements. Show your working [2 mks] (d) People handling radioactive substances need to take certain safety precautions. (i) Explain why safety precautions are necessary. [2 mks] (ii) State two safety precautions used by people handling radioactive substances. [2 mks](a) What is meant by radioactive decay? [1 mk] (b) Fig. 5.1 shows two samples of the same radioactive substance. The substance emits p-particles Fig. 5.1 Which of the following quantities is the same for both samples? [1 mk] - Half-life -Mass Number of atoms decaying each second Number of B-particles emitted each second (c) Fig. 5.2 shows the decay curve for a particular radioactive substance. Fig. 5.2 2500 count rate countsimi 2000