Physics
waves interference
Reflection
1. draw the diagrams after the pulse reflection
a. free end
b. Fix end
2. Use the figure below to complete the table
Less dense
More dense
Wave speed
Wavelength
Frequency
3. Compare the energy of the incident wave to the energy of the reflected wave.
4. Exercise 70 P. 403
When a wave crosses a boundary between a thin rope and a thick rope, as shown in Figure 23, its
wavelength and speed change, but its frequency does not. Explain why the frequency is constant.
5. A pulse in a denser medium is traveling towards the boundary with a less dense medium.
A. The reflected pulse in medium ________ (will, will not) be inverted because _______.
B. The speed of the transmitted pulse will be ___________ (greater than, less than, the
same as) the speed of the incident pulse.
C. The speed of the reflected pulse will be ______________ (greater than, less than, the
same as) the speed of the incident pulse.
D. The wavelength of the transmitted pulse will be ___________ (greater than, less than,
the same as) the wavelength of the incident pulse.
E.
The frequency of the transmitted pulse will be ___________ (greater than, less than,
the same as) the frequency of the incident pulse
6. Which of the other diagrams—(A), (B), (C), or (D)—best shows how the resultant wave
compares to the two identical waves?
7. Which of the other diagrams—A, B, C, and D—best shows how the resultant wave compares to
the two identical waves?
8. The result of the superposition of two or more waves is called ………………………………..
9.
two blue and purple waves will undergo _________________ when they meet
A. Constructive interference
B. Destructive interference
10. Q76 .Sketch the result for each of the three cases shown in Figure 24, when the centers of the
two ap proaching wave pulses lie on the dashed line so that the pulses exactly overlap.
11. skitch the resultant wave
Standing waves
1. The diagram shows the standing wave pattern of a vibrating string which is fixed at ends X and
Y. Which one of these statements is true?
A. P to R is one wavelength.
B. At R the string will move up.
C. The lowest frequency for this string is one third of its current value.
D. The kinetic energy of the string is at its maximum value
2. Which harmonic is shown?
1.
1st
2. 2nd
3. 3rd
4. 4th
3. If a standing wave is produced in three parts, how
many nodes will be produced?
A.
B. 3
C. 4
D. 7
E. 5
4. What are the boundary conditions for the standing waves?
A. Anti-nodes at each end.
B. The surface of the string is smooth.
C. The string is free at both ends.
D. There is a node at each end.
5. Standing waves are created by
A. Two identical waves reflecting off each other
B. Two identical waves being diffracted together
C. Two identical waves move through each other in opposite direction
D. Two identical waves are diffracted from two identical sources
6.
Standing wave patterns produced in a medium are constrained to integer or halfinteger multiples of resonant wavelengths. If a rope is fixed at both ends 1 m apart, which
wavelength below could not possibly produce a standing wave?
A. 2 m
B. 1/3 m
C. 1/4 m
D. 3 m
7.
The figure represents a string of length L, fixed at both ends, vibrating in several
harmonics. Which string shows the 4th harmonic?
A
B
C
D
E
8.
Exercise 78 P.404 Standing waves are created in the four strings shown in Figure 25.
All strings have the same mass per unit length and are under the same tension. The lengths of
the strings, L, are given. Rank the frequencies of the oscillations, from largest to smallest.
(Level 2)
2D WAVES
1. A vertical stick is dipped up and down in water at P. In two seconds, three wave crests are
produced on the surface of the water. Which statement is correct?
a. Distance X is the amplitude of the waves.
b. Distance Y is the wavelength of the waves.
c. Each circle represents a wavefront.
d. The frequency of the waves is 3H
2. What are the missing components, A and B in the
illustration that shows the law of reflection?
3. Light waves moving in air is reflected. What change when this happens?
a. direction
b. frequency
c. speed
d. wavelength
4. The illustration shows a light ray striking an object. IN the illustration, the light ray striking the
object isa. absorbed
b. stopped
c. reflected
d. refracted
5. In the diagram, which letter represents the angle of incidence?
A. A
B. B
C. CD
D.
6. ........... – the angle between the normal and the reflected ray.
a. Angle of incidence
b. Angle of reflection
c. Angle of coincidence
d. Angle of direction
7. If the angle of incidence is 35 degrees, what is the angle between the incident ray and
reflecting surface
A. 55
B. 90
C. 180
D. none of the above
8. Water waves may be used to demonstrate refraction by making them pass into water of a
different depth. Why does the water wave change direction as it passes into the shallow water?
A. The frequency of the wave decreases.
B. The frequency of the wave increases.
C. The speed of the wave decreases.
D. The speed of the wave increases.
9. The diagram shows a wave moving into shallower water. The wavelength of the waves is
reduced because
A. both the frequency and the speed decrease
B. both the frequency and the speed increase.
C. only the frequency increases.
D. only the speed decreases
10. he dipper in a ripple tank vibrates at a frequency
of 4.0 Hz and the resulting wave pattern is photographed. Find the wavelength
a. 20 cm
b. 4.0 cm
c. 10 cm
d. changing wavelength
11. Find the speed of that wave
4 cm / s
5 cm / s
16 cm / s
20 cm / s