1.1. A teacher carries out two experiments at the same time.

In the first experiment the count rate for a sample of a radioactive isotope is measured every 30 seconds for 6 minutes.

The results are shown in Table 12.1.

Estimate the half-life of the radioactive isotope. Use the information in the table.

half-life = ...................................................... minutes

1.2. In the second experiment the teacher repeats the procedure with another sample of the same radioactive isotope. The mass of the second sample is greater than that of the first sample.

Suggest a value for the count rate for this sample at the start of the experiment.

 count rate = ...................................................... counts/second

1.3. One type of particle emitted during radioactive decay is an α-particle (alpha particle).

Describe:  

(i) the nature of an α-particle

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(ii) the ionising ability of an α-particle

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(iii) the penetrating ability of an α-particle.

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