Available practice: 75 of 80 marks. Parts 3(b), 6(a)(i) await marking support. Scores cover available parts only.
(a)State a typical value for the speed of sound in air.
Answer guidance
State A short answer. No explanation is needed, and adding one cannot earn extra marks.
[1 mark]
A sound wave in air has a wavelength of 22 mm.
(b)Using your value for the speed of sound in air, calculate the frequency of the sound wave.
Answer guidance
Using You must use the thing it names. An answer that reaches the right value another way may not score.
[2 marks]
Fig. 7.1 shows a solid block made from hot liquid metal. As the liquid cooled, a bubble formed inside the block. The bubble is not visible from outside the block.
(c)Describe and explain how to use ultrasound to determine the size and position of the bubble inside the metal block. You may draw on the diagram.
Answer guidance
Describe Say what happens, in order. Reasons are not required unless the question also asks why.
