Page 211 - text book form physics kssm 2020

Chapter 5
Waves
Diff raction of waves is the spreading of waves when the SMART
SMART
waves propagate through a slit or side of a barrier. Th e eff ects of INFO
diff raction on the characteristics of waves are summarized in The larger the amplitude, the
Table 5.7. larger the energy carried by
the wave.

Table 5.7 Eff ects of the diff raction on characteristics of waves
Characteristic of Change caused by
Explanation
wave diff raction
Wavelength No change Wave speed does not change.
Frequency No change No change to source of frequency.

Speed No change No change in medium before and aft er
diff raction.

Amplitude Decreased Wave energy diverges and spread out to a wider
region

Direction of From one direction to many Wavefront spreads.
propagation directions

Th e fi gures below show the pattern of diff raction of water, light and sound waves.

Wave diffracted

Incident wave

Source
of sound
Waves spread
around corners
of building
Building
Building

Figure 5.49 Diff raction pattern of water wave Figure 5.50 Diff raction pattern of sound wave

Diff raction pattern through single slit Diff raction pattern through pin hole

Figure 5.51 Diff raction patterns of light waves
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5.5.1
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