A family fits loft insulation above the ceiling of their home.
The insulation is made from fibres with air held in small pockets between them.
State why holding the air in small pockets reduces energy transfer by convection.
The family increases the thickness of the loft insulation.
State why this reduces the rate of energy transfer by conduction through the roof.
State what is meant by thermal conductivity.
100 exam-style questions on Edexcel GCSE Physics 3.2 Dissipation and efficiency, covering 3.2.1 Dissipation of energy, 3.2.2 Reducing unwanted energy transfers, 3.2.3 Efficiency, and 3.2.4 Increasing efficiency. Each one has a worked solution and a mark scheme showing where the marks go.