CIE iGCSE Co-Ordinated Science P2.2.1 Thermal expansion of solids, liquids and gases Exam Style Questions Paper 3
Question
One arrow has been drawn for you.
Most-appropriate topic codes (Cambridge IGCSE Co-ordinated Sciences 0654):
• Topic P2.3.2 — Convection (Part (a))
• Topic P2.2.1 — Thermal Expansion of Solids, Liquids and Gases (Part (b))
• Topic P3.4 — Sound (Part (c)(i))
• Topic P4.5.3 — Magnetic effect of current (Part (c)(ii))
▶️ Answer/Explanation
(a)(i) Arrow rising from the heater, moving across the ceiling, dropping down the far wall, and moving back along the floor toward the heater
Warm air rises because it becomes less dense.
It cools as it moves along the ceiling and across, then sinks and returns along the floor, forming a complete convection current loop.
(a)(ii) Convection
Convection is the transfer of thermal energy through the bulk movement of a fluid (here, warm air rising and cool air sinking).
(b)(i) Celsius
The scale shown (with markings such as −10 to 110 °C) is the Celsius temperature scale.
(b)(ii) Alcohol (or mercury)
Both alcohol and mercury are commonly used liquids in liquid-in-glass thermometers.
(b)(iii) Volume (or density)
As temperature increases, the liquid expands, increasing its volume (and decreasing its density), which is used to indicate temperature change.
(c)(i) There is no medium for sound to travel through in a vacuum
Sound is a mechanical wave that requires particles to vibrate and pass on the wave.
A vacuum contains no particles, so sound has nothing to propagate through.
(c)(ii) Field lines run parallel and close together inside the solenoid (like a bar magnet), curving out and around the outside from one end to the other
Inside the solenoid, the magnetic field is strong and uniform, with lines running along the axis.
Outside, the field lines curve from the north end to the south end, similar to a bar magnet’s field pattern.
Question
The density of steel is \(7870\,\text{kg/m}^3\).
Calculate the volume of steel used to make the steel rail.
The gravitational force \(g\) on unit mass is \(10\,\text{N/kg}\).
Most-appropriate topic codes (Cambridge IGCSE Co-ordinated Sciences 0654):
• Topic P1.2 — Motion: speed-time graphs and area under graph (Part (a))
• Topic P2.2.1 — Thermal expansion of solids (Part (b)(i))
• Topic P1.3/P1.4 — Weight and Density (Part (b)(ii))
▶️ Answer/Explanation
(a)(i) 1200 s
The time taken for the journey is read directly from the graph.
The graph runs from \(t = 0\,\text{s}\) at X to \(t = 1200\,\text{s}\) at Y.
(a)(ii) Any point marked C on the flat (horizontal) section of the graph, between 200 s and 800 s
A horizontal section of a speed–time graph represents an unchanging speed.
Between 200 s and 800 s the speed stays constant at 25 m/s, so any point in this region is valid.
(a)(iii) Distance = 22 500 m
Distance travelled is found from the area under the speed–time graph.
Area \(= \left(\tfrac{1}{2} \times 200 \times 25\right) + (600 \times 25) + \left(\tfrac{1}{2} \times 400 \times 25\right) = 2500 + 15\,000 + 5000 = 22\,500\,\text{m}\).
(b)(i) The gaps allow the rails to expand in hot weather without buckling
In hot weather, the steel rails expand due to thermal expansion.
The gaps provide space for this expansion, preventing the rails from bending or buckling.
(b)(ii) Volume = 0.13 m³
First find the mass of the rail using \(W = mg\), so \(m = \dfrac{W}{g} = \dfrac{10270}{10} = 1027\,\text{kg}\).
Then use \(\rho = \dfrac{m}{V}\), rearranged to \(V = \dfrac{m}{\rho} = \dfrac{1027}{7870} \approx 0.13\,\text{m}^3\).