Exercises: Impact on science, society and environment

Wind turbines are used on the west coast of Ireland to generate electricity. Name one benefit and one drawback of wind energy for the environment or for local people.

Name two technologies based on physics that are used in medicine (for example in a hospital in Dublin) and state one way each helps patients.

Solar panels are fitted to the roof of a school. State the energy transformation that occurs in a solar panel and name one advantage of using solar panels compared with burning fossil fuels.

A household replaces five $60\ \text{W}$ filament bulbs with five $8\ \text{W}$ LED bulbs. Each is used for $4$ hours per day.

1. a) Calculate the energy saved per day in kWh.

1. b) Calculate the saving per year ($365$ days) if electricity costs €0.30 per kWh.

1. c) Suggest one environmental benefit of this change.

A community near Limerick is considering a new wind farm of $10$ turbines, each with a power output of $3.0\ \text{MW}$ when running. The turbines operate at an average of $35\%$ of their maximum output.

1. a) Calculate the maximum power of the whole wind farm in MW.

1. b) Calculate the average power output in MW.

1. c) Calculate the energy produced in one day in MWh.

1. d) Discuss one social and one environmental issue the community should consider.

Mobile phone technology has changed how people communicate. Phones use electromagnetic waves, travelling at $3.0 \times 10^{8}\ \text{m/s}$.

1. a) Calculate the time for a signal to travel $300\ \text{km}$ from a mast to a phone.

1. b) State one scientific, one social and one environmental impact of mobile phone technology.

A power station burns peat to produce electricity. A proposal suggests replacing it with a combination of wind and solar power plus a pumped-storage hydroelectric plant.

1. a) Explain the role of pumped storage in dealing with the variable output of wind and solar.

1. b) Evaluate the proposal, giving two environmental and two social advantages and disadvantages.

1. c) State what additional information you would need to make a fully informed decision.

An electric car has a battery of capacity $60\ \text{kWh}$ and travels $400\ \text{km}$ on a full charge. A petrol car uses $6.0$ litres per $100\ \text{km}$ and petrol releases about $2.3\ \text{kg}$ of $\text{CO}_2$ per litre. Assume electricity in Ireland produces $0.30\ \text{kg}$ of $\text{CO}_2$ per kWh.

1. a) Calculate the $\text{CO}_2$ emitted by the petrol car per $100\ \text{km}$.

1. b) Calculate the $\text{CO}_2$ attributable to electricity for the electric car per $100\ \text{km}$.

1. c) Discuss, with reasons, whether the electric car is better for the environment, mentioning one factor not included in your calculation.

X-rays and MRI scans are widely used in hospitals. X-rays use ionising radiation; MRI uses magnetic fields and radio waves.

1. a) Explain why ionising radiation carries a risk and why X-ray exposure is limited.

1. b) Compare the two technologies in terms of benefits and risks, identifying one situation where each is more appropriate.

1. c) Discuss one ethical or cost-related issue that arises when deciding who receives scans.