1. Diagram 1.1 shows the propagation of wavefronts of sound waves at daytime while, Diagram 1.2 shows the propagation during at night..

Diagram 1.1 Diagram 1.2

(a) Based on diagram 1.1 and diagram 1.2, compare (i) the density of air close the ground and density of air at the upper path. (ii) direction of propagation of wave. (iii) the loudness of the sound waves that can be heard by the girl.

[ 3 marks ]

(b) Hence, find the relationship between the density of air, the loudness and direction of propagation to explain the phenomena observed. [1 mark ]

2. Diagram 2.1 shows the pattern of the water wave after passing through a gap. The experiment was repeated with different wavelength of waterpassing through the same gap. The wave pattern is as shown in Diagram 2.2.

Diagram 2.1 Diagram 2.2

(a) What is wavelength? [1 mark ] (b) Based on Diagram 2.1 and Diagram 2.2, compare (i) the wavelength before passing through the gap (ii) the wavelength before and after passing through the gap

[2 marks]

(c) Compare the wave pattern in Diagram 2.1 and Diagram 2.2 after the wave passed through the gap.

[1 mark] (d) Based on your answers in ( b) and (c), state the relationship between the wavelength and the wave pattern after passing through the gap. [1 mark]

(e) Name the wave phenomenon which occurs in Diagrams 2.1 and 2.2. [1 mark]

3. A wooden bar P vibrates on a water surface of a ripple tank at a frequency of 5 Hz. The water wave produced is shown in the diagram 3.1 below.

(i) The distance between three consecutive crests is 8.0 cm. What is the wavelength, λ, of the water wave? (ii) What is the frequency of the water wave? (iii) Calculate the speed of the water wave in the ripple tank. [5marks]

4. Diagram 4.1, shows the location of housing area. The residents of housing area at P receive clearer television signal compare to the residents of housing area at Q where it is located behind the hill.

3.1

Diagram 4.1

As a researcher, you are required to give suggestions about the modifications of transmission television signal from broadcasting station so that the residents of housing area at Q are enable to receive better signal. State and explain the modification based on the following aspects: (i) the frequency of the signals (ii) the location of the transmitter (iii) the number of the transmitter (iv) the strength of the signals (v) the distance between two transmitters [10 marks]