Edexcel A-Level Physics Heating and Latent Heat Equations

Practise Edexcel A-Level Physics heating and latent heat equations by calculating energy transfers, temperature changes and phase-change masses.

Exam points

calculate energy transfer using ΔE = mcΔθ with mass, density and temperature data
use ΔE = LΔm to find latent heat, boiled-away mass or energy during a change of state
evaluate heating or cooling claims by linking energy transfer, power and time from data

[Maximum number: 3]

The water in a swimming pool at the Olympic Games should be at a temperature of $28.0^{\circ}\mathrm{C}$ .

A pool contains $2750\,\mathrm{m^3}$ of water at $16.5^{\circ}\mathrm{C}$ .

Calculate the increase in internal energy $\Delta E$ of the water when it is heated to $28.0^{\circ}\mathrm{C}$ .

Density of water $=998\,\mathrm{kg\,m^{-3}}$

Specific heat capacity of water $=4190\,\mathrm{J\,kg^{-1}\,K^{-1}}$

Use ho=m/V, so $m= ho V=(998)(2750)=2.74 imes10^6\,\mathrm{kg}$ . Then

$\Delta E=mc\Delta T=(2.74 imes10^6)(4190)(28.0-16.5)=1.32 imes10^{11}\,\mathrm{J}.$

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5.3.125 - Heating and latent heat equations question 1