Question 23
Question 23 of 40

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No letter options?
Older MCQs might not have the typical A, B, C, D choices. They have choices 1, 2, 3, and a combination of them is the answer. Below is the key that maps such combinations to the answer.
A 1, 2 and 3 are correct
B 1 and 2 only are correct
C 2 and 3 only are correct
D 1 only is correct

Topics Tested

Know that a medium is needed to transmit sound waves

Describe how waves can undergo: (a) reflection at a plane surface (b) refraction due to a change of speed (c) diffraction through a narrow gap