CIE iGCSE Co-Ordinated Science P2.3.3 Radiation Exam Style Questions Paper 3
Question
(a) Fig. 12.1 shows an electric heater used in a classroom in a school.
The air around the heater is warmed.
(i) On Fig. 12.1 draw three more arrows to show how the warmed air moves around the classroom.
One arrow has been drawn for you.
(ii) State the name of the method of thermal energy transfer you have drawn in (a)(i).
(b) The teacher in the classroom measures the temperature in the room with a thermometer.
Fig. 12.2 shows the thermometer.
(i) State the name of the temperature scale used on the thermometer.
(ii) State the name of a liquid that is used in thermometers.
(iii) State the physical property of the liquid that varies with temperature.
(c) (i) In the school an electric bell rings to show that the lesson has ended.
The bell makes sound waves that travel through the air.
Sound waves cannot travel through a vacuum.
Explain why sound cannot travel through a vacuum.
(ii) Inside the electric bell there is a solenoid.
The solenoid coil is shown in Fig. 12.3.
On Fig. 12.3, draw the pattern of the magnetic field that is produced when an electric current passes through the solenoid as shown.
▶️Answer/Explanation
Ans : 12(a)(i) arrow
across the top
then dropping down
then left to right along floor
1 mark for any one correct arrow ;
1 mark for all three arrows correct ;
12(a)(ii) convection ;
12(b)(i) celsius ;
12(b)(ii) alcohol or mercury ;
12(b)(iii) volume / density ;
12(c)(i) There is no medium (for the propagation of the sound wave) ;
12(c)(ii) at least two lines going all the way through coil ;
line curving upwards and line curving downwards ;
Question
9. (a) On Fig. 9.1, draw one straight arrow to show the movement of the air cooled by the freezing compartment.
▶️Answer/Explanation
Answer: vertical arrow downwards
Sub-topic Code: P4.1 (Thermal Properties)
Detailed Solution: The cooled air moves downwards due to its higher density compared to the warmer air in the refrigerator.
9. (b) Describe two differences between the particle arrangement in a liquid and in a solid as shown in Fig. 9.2.
▶️Answer/Explanation
Answer: solid has regular arrangement / liquid has irregular arrangement; particles are further apart in a liquid
Sub-topic Code: P4.1 (States of Matter)
Detailed Solution: In a solid, particles are arranged in a regular, fixed pattern, while in a liquid, the arrangement is irregular. Additionally, particles in a liquid are further apart compared to those in a solid.
9. (c) (i) Show that the resistance of the lamp is 6000 Ω.
▶️Answer/Explanation
Answer: \( R = \frac{V}{I} = \frac{240}{0.04} = 6000 \, \Omega \)
Sub-topic Code: P9.1 (Electric Circuits)
Detailed Solution: Using Ohm’s Law, \( R = \frac{V}{I} \), where \( V = 240 \, V \) and \( I = 0.04 \, A \). Thus, \( R = \frac{240}{0.04} = 6000 \, \Omega \).
9. (c) (ii) State the correct value for the combined resistance of two lamps connected in parallel and explain your answer.
▶️Answer/Explanation
Answer: 3000 Ω; combined resistance of two resistors in parallel is less than that of either resistor by itself
Sub-topic Code: P9.1 (Electric Circuits)
Detailed Solution: When two resistors of equal resistance (6000 Ω) are connected in parallel, the combined resistance is half of one resistor, i.e., 3000 Ω. This is because the total resistance in parallel is always less than the smallest individual resistance.
9. (d) State two other ways to increase the turning effect of the motor.
▶️Answer/Explanation
Answer: increase current; increase number of turns on coil
Sub-topic Code: P11.1 (Electromagnetism)
Detailed Solution: The turning effect of a motor can be increased by increasing the current flowing through the coil or by increasing the number of turns on the coil, which increases the magnetic field strength.