a) Radioactive materials are used in nuclear power stations to generate electricity - Edexcel - GCSE Physics - Question 2 - 2018 - Paper 1

To calculate the remaining mass of cobalt-60 after 10 years, we use the formula for half-life:

If the half-life is 5 years, then for 10 years, there are:

$n = \frac{10 \text{ years}}{5 \text{ years/half-life}} = 2 \text{ half-lives}$

Starting mass = 16.0 mg. After 1 half-life:

$16.0 \text{ mg} \times \frac{1}{2} = 8.0 \text{ mg}$

After 2 half-lives:

$8.0 \text{ mg} \times \frac{1}{2} = 4.0 \text{ mg}$

Thus, the mass of cobalt-60 remaining after 10 years is 4.0 mg.

Workers at a nuclear power station can be exposed to radiation, which can lead to ionization of cells. This ionizing radiation can cause damage to DNA, potentially leading to cancer or other illnesses. Long-term exposure without adequate protection can accumulate and significantly increase the risk of serious health effects.