A student investigated the insulating properties of different materials - AQA - GCSE Physics - Question 4 - 2022 - Paper 1

To calculate the mass ($m$) of the water, we can use the formula for energy transfer:

$E = mc heta$

where:

• $E$ = energy transferred (10,500 J)
• $c$ = specific heat capacity of water (4200 J/kg °C)
• $heta$ = temperature change (85 - 65 = 20 °C)

Rearranging the formula gives: $m = \frac{E}{c\theta}$

Substituting the values:

$m = \frac{10,500}{4200 \times 20} = 0.125 \text{ kg}$.

The results in Table 2 show that material X took 450 seconds to decrease in temperature by 20 °C, whereas material Y took 745 seconds. Since a shorter time for temperature decrease indicates higher thermal conductivity, it can be concluded that material X has a higher thermal conductivity than material Y.