CAPE Physics Unit 1 · 2008 · Paper 2 · Question 6(a)(i)

A scientist is investigating the rate of conduction, P, of thermal energy through various thicknesses, x, of a material for supermarket cold room walls. Figure 6 shows results for samples with an area of 0.25 m², for fixed inside and outside temperatures of -5 °C and 30 °C respectively.

Write a formula relating P to the inside and outside temperatures of the material, θ₁ and θ₂, and the thickness, x.

This question uses a figure or table from the paper — you'll see it when you practise.