CIE iGCSE Co-Ordinated Science P2.3.1 Conduction Exam Style Questions Paper 4
Question
The student repeats the experiment using different thicknesses of cotton wool.
Fig. 9.1 shows a graph of the results.
Use the results shown in Fig. 9.1 to explain your answer.
The digital thermometer contains two wires made of different metals.
The wires are joined together at each end to form two junctions.
This arrangement is known as a ____.
(i) Explain what is observed when the two plastic sheets are moved close to each other.
Most-appropriate topic codes (Cambridge IGCSE Co-ordinated Sciences 0654, 2025–2027 syllabus):
• Topic P2.3.1 — Conduction (Part (a)(i))
• General physics knowledge — temperature sensors (Part (a)(ii))
• Topic P4.2.4 — Resistance (Part (b))
• Topic P4.2.1 — Electrical charge (Part (c))
▶️ Answer/Explanation
(a)(i) Any value from 36°C to 50°C
A 2.0 cm thickness lies between the 1.0 cm and 3.0 cm curves shown on the graph.
Since 2.0 cm reduces the rate of heat loss (conduction to the surroundings) more than 1.0 cm of insulation but less than 3.0 cm, its final temperature should lie between the two curves at 5.0 minutes.
(a)(ii) Thermocouple
Two different metal wires joined at two junctions form a thermocouple, which generates a small voltage dependent on the temperature difference between the junctions, allowing temperature to be measured electronically.
(b) \(32\,\Omega\)
Current is found using \(I = \dfrac{P}{V} = \dfrac{1800}{240} = 7.5\,\text{A}\).
Resistance is then found using \(R = \dfrac{V}{I} = \dfrac{240}{7.5} = 32\,\Omega\).
(c)(i) They move apart
Both plastic sheets carry the same (positive) charge.
Like charges repel each other, so the sheets will move apart/swing away from each other.
(c)(ii) Charging by friction
Rubbing the plastic sheet against another surface causes friction between the two materials.
This transfers electrons from the plastic sheet to the other surface, leaving the plastic sheet with an overall positive charge (a deficit of electrons).
Question
- peak X is positive and peak Y is negative
- peak Y has a larger magnitude than peak X
On Fig. 9.2, sketch the data which would be obtained if a coil containing 400 turns was used with the same magnet.
Place ticks in Table 9.1 against each statement that is correct for potential difference and for electromotive force (e.m.f.).
You may place one or two ticks in each row. The first row has been done for you.
In a solid, the arrangement of atoms is ……………………… .
The forces between atoms are ……………………… which allows the atoms to ……………………… but keeps them in a ……………………… position.
Describe how thermal energy is transferred in copper.
Most-appropriate topic codes (Cambridge IGCSE Co-ordinated Sciences 0654):
• Topic P4.5.1 — Electromagnetic induction (Part (a))
• Topic P4.2.3 — Voltage (electromotive force and potential difference) (Part (b))
• Topic P2.1.1 — States of matter (Part (c))
• Topic P2.3.1 — Conduction (Part (d))
▶️ Answer/Explanation
(a)(i) The S pole causes peak X; the N pole causes peak Y; the magnet’s speed increases as it falls
As the magnet falls, its south pole passes through the coil first, inducing the positive peak X.
Its north pole passes through next, inducing the negative peak Y.
Peak Y is larger because the magnet has accelerated under gravity and is moving faster by the time its north pole passes through, inducing a greater e.m.f.
(a)(ii) Same shape graph, crossing the x-axis at the same point, but with both peaks lower
Halving the number of turns halves the induced e.m.f. at every point, since e.m.f. is proportional to the number of turns.
The overall shape and timing of the graph remain unchanged since the magnet’s motion is unaffected.
(b)
E.m.f. relates to the energy supplied by the source, while potential difference relates to the energy transferred by a circuit component.
Both are equal to work done per unit charge and are measured in volts.
(c) Regular/ordered (a lattice); strong forces; vibrate; fixed position
In a solid, atoms are arranged in a regular, ordered lattice.
Strong forces of attraction hold the atoms close together, allowing them only to vibrate about fixed positions rather than move freely.
(d) Atoms vibrate; vibrations pass to neighbouring atoms; free electrons also transfer energy
Atoms in copper vibrate more vigorously when heated.
These vibrations are passed on from atom to atom through the lattice.
Copper’s free (delocalised) electrons also move and transfer thermal energy quickly through the metal.