State the name given to sound waves with a frequency greater than 20 kHz20\text{ kHz}20 kHz.
A research vessel uses sound waves to measure the depth of a lake. The speed of sound in the water is 1480 m/s1480\text{ m/s}1480 m/s. The lake bed is at a depth of 74 m74\text{ m}74 m directly below the vessel. Calculate the time taken for the vessel to receive the reflected wave from the lake bed after the pulse is emitted.
A single fish is swimming directly below the vessel, between the vessel and the lake bed. Describe and explain two ways in which the reflected sound wave received from the fish differs from the reflected sound wave received from the lake bed.
295 exam-style questions on CIE IGCSE Physics Sound, covering Sound. Each one has a worked solution and a mark scheme showing where the marks go.