In an experiment, a thermometer is placed in a test-tube of hot liquid. The temperature of the liquid is recorded every half minute. The table shows the results.
time / minutes0.00.51.01.52.02.53.03.54.04.55.05.56.06.57.07.5temperature / ∘C68595144444444403633312927262524 \begin{array}{|l|c|c|c|c|c|c|c|c|c|c|c|c|c|c|c|c|} \hline \text{time / minutes} & 0.0 & 0.5 & 1.0 & 1.5 & 2.0 & 2.5 & 3.0 & 3.5 & 4.0 & 4.5 & 5.0 & 5.5 & 6.0 & 6.5 & 7.0 & 7.5 \\ \hline \text{temperature / } ^\circ\text{C} & 68 & 59 & 51 & 44 & 44 & 44 & 44 & 40 & 36 & 33 & 31 & 29 & 27 & 26 & 25 & 24 \\ \hline \end{array} time / minutestemperature / ∘C0.0680.5591.0511.5442.0442.5443.0443.5404.0364.5335.0315.5296.0276.5267.0257.524What is the melting point of the substance?
0∘C0^\circ\text{C}0∘C
24∘C24^\circ\text{C}24∘C
44∘C44^\circ\text{C}44∘C
68∘C68^\circ\text{C}68∘C
313 exam-style questions on CIE IGCSE Physics 2.2.3a Melting, boiling, condensation and solidification. Each one has a worked solution and a mark scheme showing where the marks go.