Page 16 - Spotlight A+ Physics Form 4.5

Form
4 Physics Chapter 5 Waves

Applications of Diffraction of Waves in Daily Life
1. Diffraction of water, light and sound waves have their applications in daily life.

Gap
Water waves
• Diffraction of water waves when moving through
a gap produces a region of calm water suitable for Region of
calm water
berthing of ships and water recreational activities.
©PAN ASIA PUBLICATIONS
©PAN ASIA PUBLICATIONS
Light waves
• Holograms produced by the diffraction of light is
used as a security mark in bank cards such as the
debit card and credit card.

Sound waves
• Infrasonic sound waves with long wavelength
produced by elephants enables long distance
communication between elephants.

5.5

1. Figure 5.48 shows water waves approaching a gap in a Barrier Gap
ripple tank.
(a) Draw the wave pattern formed to show the wave Ripple
phenomenon that occurs. C3 tank
(b) What happens to the amplitude of water waves after
passing through the gap? C4

Figure 5.48

2. Figure 5.49 shows an audio generator and loudspeaker placed near the corner of a building. Three
students, A, B and C are standing around the corner. The audio generator can produce sounds with
different pitch.
C
B A
CHAP
5
Loudspeaker

Audio generator
Figure 5.49
(a) State one factor that affects the pitch of the sound. C2
(b) When a high pitch sound is generated, only student A can hear the sound clearly. When a low pitch
sound is generated, all three students can hear the sound clearly. Explain this situation. C3

158 5.5.4