Page 232 - text book form physics kssm 2020

3. Figure 3 shows superposition of two coherent plane waves.
(a) What is a coherent wave? P Q
(b) State the points where the following occur R
S
(i) constructive interference,
(ii) destructive interference.
(c) Explain with suitable diagrams, interference at point
(i) Q,
(ii) R, and
(iii) S. Key:
Crest
Trough
4. Figure 4 shows the apparatus set up of Young’s double-slit
experiment.
Figure 3
Transparent screen
Young’s
Blue filter double-slit
Bright fringe
Dark fringe
a K
x

Ray box Single slit
D

Figure 4
(a) What happens to the light rays at area K?
(b) Explain the formation of bright fringes and dark fringes on the screen.
(c) You are given the following information:
• Distance between double slits, a = 0.30 mm
• Distance between double-slits and screen, D = 2.70 m
• Separation distance between two adjacent bright fringes, x = 4.0 mm
Calculate the wavelength, λ of blue light in this experiment.

5. A student moves a slinky spring repeatedly at a 1.2 m
frequency of 5 Hz so that a transverse wave is
produced as shown in Figure 5.
(a) Determine the amplitude, period and
wavelength of the wave. 15 cm
(b) Calculate the wave speed along the slinky
spring.
Figure 5
6. A judge blew a whistle which produced a sound of frequency 500 Hz and a wavelength
of 0.67 m in the air. What is the wave speed of the sound?

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