Polarisation: past paper questions
Real questions on polarisation
The newest 18 of 18 written questions. Open one to see it on the real paper.
- 9702/43 · October/November 2025 · Q10a[2]
Define specific acoustic impedance.
See it on the paper → - 9702/43 · October/November 2025 · Q10b[2]
Explain how ultrasound waves are detected by a piezoelectric crystal.
See it on the paper → - 9702/43 · October/November 2025 · Q10c(i)[2]
Calculate the intensity reflection coefficient for ultrasound incident on a water–steel boundary. intensity reflection coefficient =
See it on the paper → - 9702/43 · October/November 2025 · Q10c(ii)[2]
Explain, without calculation, what is likely to happen when ultrasound is incident on a body tissue–water boundary.
See it on the paper → - 9702/23 · May/June 2025 · Q5b(i)[3]
On Fig. 5.2, sketch the variation of the intensity I of the transmitted light with the angle of rotation α as the filter is rotated through 360° from its initial position. I 0 I 0 90 180 270 α / ° 360 0 I 0 2
See it on the paper → - 9702/23 · May/June 2025 · Q5b(ii)[4]
The amplitude of the incident light wave is A 0 when the intensity of the wave is I 0 . Use Malus’s law to determine, in terms of A 0 , the amplitude of the transmitted wave when α = 20°. amplitude = A 0
See it on the paper → - 9702/42 · February/March 2025 · Q4d(i)[2]
The crystal is made from piezoelectric material. Explain how the crystal is made to vibrate.
See it on the paper → - 9702/22 · October/November 2023 · Q5a(i)[2]
The transmission axis of the filter is initially vertical. The filter is then rotated through an angle of 360° while the plane of the filter remains perpendicular to the beam. On Fig. 5.2, sketch a graph to show the variation of the intensity of the light in the transmitted beam with the angle through which the transmi...
See it on the paper → - 9702/22 · October/November 2023 · Q5a(ii)[2]
The intensity of the light in the incident beam is 7.6 W m –2 . When the transmission axis of the filter is at angle θ to the vertical, the light intensity of the transmitted beam is 4.2 W m –2 . Calculate angle θ . θ = °
See it on the paper → - 9702/22 · May/June 2023 · Q5c(i)[1]
Show that the intensity of the light transmitted by the first filter is 5.7 W m –2 .
See it on the paper → - 9702/21 · October/November 2022 · Q4a(i)[1]
State the meaning of polarisation.
See it on the paper → - 9702/21 · October/November 2022 · Q4a(ii)[1]
State why light waves can be plane polarised but sound waves cannot.
See it on the paper → - 9702/21 · October/November 2022 · Q4b[3]
Two polarising filters A and B are positioned so that their planes are parallel to each other and perpendicular to a central axis line XY, as shown in Fig. 4.1. filter A filter B direction of rotation I 0 X Y unpolarised light vertical transmission axis horizontal transmission axis Fig. 4.1 The transmission axis of fil...
See it on the paper → - 9702/22 · October/November 2022 · Q5c(i)[2]
the ratio I 1 I 0 I 1 =
See it on the paper → - 9702/22 · October/November 2022 · Q5c(ii)[2]
the ratio 0 I 2 . I 0 I 2 = I 0
See it on the paper → - 9702/22 · February/March 2022 · Q5c(i)[3]
By considering the ratio T , calculate the ratio I 0 amplitude of transmitted light . amplitude of incident light Show your working. ratio =
See it on the paper → - 9702/22 · February/March 2022 · Q5c(ii)[1]
The filter is now rotated, about the direction of the light beam, from its starting position shown in Fig. 5.1. The direction of rotation is such that the angle of the transmission axis to the vertical initially increases. Calculate the minimum angle through which the filter must be rotated so that the intensity of the...
See it on the paper → - 9702/23 · October/November 2019 · Q5a(i)[1]
coherence
See it on the paper →
What examiners said
Examiners expected to see reference to an alternating voltage applied across the crystal, making it alternately expand and contract. Many candidates confused the concepts of a voltage being applied (to cause distortion of the crystal) with a voltage being induced in the crystal by mechanical vibrations. Some candidates confused voltage with current.
— Examiner report, February/March 2025, 9702/42 Q4(d)(i) (Cambridge)
Although many candidates correctly deduced the angles at which the intensity of the light would be maximum and zero, only a small minority were able to sketch the shape of the overall curve correctly. A common misconception was that the graph would consist of a series of straight lines forming a ‘zig-zag’ shape.
— Examiner report, October/November 2023, 9702/22 Q5(a)(i) (Cambridge)
Most candidates were able to recall the correct symbol equation. The most common mistake was to then forget that the cosine function was squared when rearranging the recalled equation. Another common mistake was to substitute the intensities of the incident light and the transmitted light the wrong way round.
— Examiner report, October/November 2023, 9702/22 Q5(a)(ii) (Cambridge)
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