Question
(a) State the name of the reflection of a sound wave or ultrasound wave
…………………………………………………………………………………………………………………………… [1]
(b) Fig. 5.1 shows an ultrasound wave being used to scan an internal organ of a human body.
The ultrasound wave has a frequency of 2.0 MHz and passes through human tissue at a speed of 1500 m / s.
Calculate the wavelength of the ultrasound wave in human tissue.
wavelength = …………………………….. [3]
(c) Fig. 5.2 shows crests of a wave from a point source S approaching a straight barrier.
On Fig. 5.2, indicate and label one wavelength.
On Fig. 5.2, draw three crests of the wave reflected from the barrier.
[3][Total: 7]
Answer/Explanation
Ans:
(a) echo
(b)
λ=7.5 × 
m
λ= v / f
OR
v = fλ in any form
λ= 1.5 × 
/ 2 × 
(c)(i),(ii)
labelled wavelength of incident wave
3 part circles to the left of the barrier and centred to right of the barrier
wavelengths of reflected and incident waves same