The thermometer has no scale. Where must the bulb be placed so that the upper fixed point of 100∘C100^\circ\text{C}100∘C can be marked on the stem?
in a freezer
in pure melting ice
in steam above pure boiling water
in cold water from a tap
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.