An electric kettle contains 1.2 kg of water at 20 ∘C20\ ^{\circ}\text{C}20 ∘C.
The kettle heats the water to 100 ∘C100\ ^{\circ}\text{C}100 ∘C.
The specific heat capacity of water is 4200 J/kg ∘C4200\ \text{J/kg}\ ^{\circ}\text{C}4200 J/kg ∘C.
Calculate the change in temperature of the water.
Calculate the energy transferred to the water.
Use the equation
ΔQ=m×c×Δθ\Delta Q = m \times c \times \Delta \thetaΔQ=m×c×Δθ
The kettle transfers more energy from the mains supply than the energy transferred to the water.
Explain why.
Suggest one way of reducing the energy wasted by the kettle.
110 exam-style questions on Edexcel GCSE Physics 14.2 Specific heat capacity and latent heat, covering 14.2.1 Heating, temperature and changes of state, 14.2.2 Specific heat capacity and specific latent heat, 14.2.3 Specific heat capacity calculation, 14.2.4 Specific latent heat calculation, and 14.2.5 Reducing energy transfer through thermal insulation. Each one has a worked solution and a mark scheme showing where the marks go.