Formative Practice 5.3 – Physics Form 4 Chapter 5

Question 1:
Copy Figure 5.32 and draw the wavefront and the direction of the reflected water waves.


Answer:

Question 2:
Figure 5.33 shows the use of ultrasonic waves by a ship to determine the depth of the sea. The interval time between transmission and receiving of echo of the ultrasonic sound is 0.06 seconds. Speed of the ultrasonic wave in the water is 1 500 m s^–1. Determine the depth of the sea.



Answer:

Speed of the wave, v = 1 500 m s^–1
Time interval, t = 0.06 s
Distance travelled = Speed × time

$$ \begin{aligned} 2 d & =v t \\ \text { Depth, } d & =\frac{v t}{2} \\ d & =\frac{1500 \times 0.06}{2} \\ & =45 \mathrm{~m} \end{aligned} $$