DP Physics (first assessment 2025)

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Question 22N.2.SL.TZ0.c.ii

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Date November 2022 Marks available [Maximum mark: 2] Reference code 22N.2.SL.TZ0.c.ii
Level SL Paper 2 Time zone TZ0
Command term Discuss Question number c.ii Adapted from N/A
c.ii.
[Maximum mark: 2]
22N.2.SL.TZ0.c.ii

The speed of sound in air is 340 m s−1 and in water it is 1500 m s−1.

Discuss whether the sound wave can enter the water.

[2]

Markscheme

ALTERNATIVE 1

critical angle =13° «from sin θc=3401500» ✓

the angle of incidence is greater than θc hence the sound can’t enter water ✓

 

ALTERNATIVE 2

sin θr=1500340sin 30° ✓

sine value greater than one hence the sound can’t enter water ✓

 

Conclusion must be justified, award [0] for BCA.

Examiners report

Surprisingly well answered as it was sound from air to water, rather than light from air to glass. A mixture of approaches but probably the most common was to calculate a sine value of over 1. Some went about calculating the critical angle but nowhere near as many.

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