Number of right solutions given by different students for the same problem	1	2	3	4	5	6	7
Points of corresponding problem	42	21	14	10.5	8.4	7	6

1. A change in the speed of a wave as it enters a new medium produces a change in (1) frequency; (2) period; (3) wavelength; (4) phase. 2. In a vacuum, all electromagnetic waves have the same (1) wavelength; (2) frequency; (3) speed; (4) amplitude 3. The speed of light (f =5.09 x 1014 Hz) in a transparent material is 0.75 times its speed in air. The absolute index of refraction of the material is approximately:____ 4. A sound of constant frequency is produced by the siren on top of a firehouse. Compared to the frequency produced by the siren, the frequency observed by a firefighter approaching the firehouse is (1) lower; (2) higher; (3) the same. 5. The diagram (Fig.1.) represents a ray of monochromatic light (f =5.09 x 1014 Hz) passing from medium X (n = 1.46) into fused quartz. Which path will the ray follow in the quartz? (Index of refraction of fused quartz: at 587.6 nm: 1.4585) (1) A; (2) B; (3) C; (4) D. 6. A wave is transporting energy from left to right. The particles of the medium are moving back and forth in a leftward and rightward direction. This type of wave is known as a: (a) surface; (b) electromagnetic; (c) transverse; (d) longitudinal. 7. Circle the type of mechanical wave that can exist in the medium indicated. Note that in some media both types exist: (T) Transverse, (L) Longitudinal. (O, Only together) Waves can not have properties of only one wave type: or longitudinal, or transverse. (N) Mechanical waves don’t exist

Fig.1.

Medium	Gas	Liquid	Solid	String	Water surface	Vacuum	Spring	Air	Electromagnetic field
Transverse	T	T	T	T	T	T	T	T	T
Longitudin	L	L	L	L	L	L	L	L	L
Only together	O	O	O	O	O	O	O	O	O
N	N	N	N	N	N	N	N	N	N

8. A wave in a string (mass per unit length µ = 8 g/m) is described by y (x,t) = (0.5 cm) sin (2 x + 8 t), where x is in meters and t is in seconds. In what direction is the wave traveling?
9. A wave in a string (mass per unit length µ = 8 g/m) is described by y (x,t) = (0.5 cm) sin (2 x + 8 t), where x is in meters and t is in seconds. What is the speed of the wave?
10. A wave in a string (mass per unit length µ = 8 g/m) is described by y (x,t) = (0.5 cm) sin (2 x + 8 t), where x is in meters and t is in seconds. What is the maximum transverse velocity of a very small segment of the string?
11. A wave in a string (mass per unit length µ = 8 g/m) is described by y (x,t) = (0.5 cm) sin (2 x + 8 t), where x is in meters and t is in seconds. What is the tension of the string?

12. A traveling wave propagates along a string of length L = 0.4 m and reflects off one end creating a standing wave with 3 loops (Fig.2.). Both ends of the string are fixed, its tension is 4N, and its mass is m = 2 g. Find the velocity of a traveling wave on that string. 13. A pipe has a length of L = 1.23 m. Find the frequencies fi, i = 1, 2 of the first two harmonics if the pipe is open at both ends. The speed of sound in air is v = 343 m/s.

Fig.2.

14. A pipe has a length of L = 1.23 m. Find the frequencies f_i, i = 1, 2 for the first two harmonics if the pipe is closed at one end.
15. A pipe has a length of L = 1.23 m. For the pipe with two open ends, find the number of harmonics with frequencies f in the hearing range, 20 Hz < f < 20,000 Hz.
16. A train moving at a speed of 40 m/s sounds its whistle, which has a frequency of 500 Hz. Determine the frequency heard by a stationary observer as he is approached by the train.
17. The roar of a Lion is 20 dB louder than the moo of a Cow. What is the ratio of their sound intensities (Ilion/Icow).
18. A sound wave traveling through a solid material has a frequency of 500 hertz. The wavelength of the sound wave is 2 meters. What is the speed of sound in the material?
19. What is length of a train if its whistle sound has a wave length of 5cm, number of railcar is 12, and train velocity is 50 km/hour?
20. When two mechanical waves coincide, the amplitude of the resultant wave is always ____ the amplitudes of each wave alone. (greater than; less than; the sum of; the same as)
21. C_A and C_B are light velocities in materials A and B. Θ_A is angle of incident ray in A, and Θ_B is angle of refraction in B. Θ_A=1^o, Θ_B =2^o. Find C_A and C_B, if you know one of them, C_A or may be C_B, equals to 2.5 x 10⁸m/s.
22. Four beats per second are heard when two notes are sounded. The frequency of one note is 420 Hz. Which of the following is a possible frequency of the other note?
23. If a guitar string has a fundamental frequency of 500 Hz, what is the frequency of its second harmonic?
24. The intensity of a sound at any distance from the source is directly proportional to the sound's: (1) wavelength; (2) pitch; (3) power; (4) frequency.
25. At a distance of 3 m, the intensity of a sound will be ____ the intensity it was at a distance of 1 m: (a) one-ninth; (b) one-third; (c) 3 times; (d) 9 times;
26. In general, sound travels faster through: (1) solids than through gases; (2) gases than through solids; (3) gases than through liquids; (4) empty space than through matter.

27. The wavelength of the wave in the diagram (Fig.3.) is given by letter __. The amplitude of the wave in the diagram above is given by letter__. 28. A marine weather station reports waves along the shore that are 2 meters high, 8 meters long, and reach the station 8 seconds apart. Determine the frequency and the speed of these waves. 29. Two waves are traveling through a container of nitrogen gas. Wave A has an amplitude of .1 cm. Wave B has an amplitude of .2 cm. The energy transported by wave B must be ___ the energy transported by wave A. (a) one-fourth; (b) one-half; (c) two times larger than; (d) four times larger than.

(Fig.3.)

30. A certain pipe produces a fundamental frequency of 262 Hz in air. a) If the pipe is filled with helium at the same temperature, what fundamental frequency does it produce? (The molar mass of air is 28.8 g/mol, and the molar mass of helium is 4.00 g/mol.)
31. The frequency of the note F4 is 349 Hz. a) If an organ pipe is open at one end and closed at the other, what length must it have for its fundamental mode to produce this note at 20.0°C? b) At what air temperature will the frequency be 370 Hz, corresponding to a rise in pitch from F to F-sharp? (Ignore the change in length of the pipe due to the temperature change.)
32. Two radio antennas A and B radiate in phase. Antenna B is 120 m to the right of antenna A. Consider point Q along the extension of the line connecting the antennas, a horizontal distance of 40 m to the right of antenna B. The frequency, and hence the wavelength, of the emitted waves can be varied. a) What is the longest wavelength for which there will be destructive (the resultant amplitude is the difference between the two individual amplitudes) interference at point Q? b) What is the longest wavelength for which there will be constructive (the amplitude of the resultant wave is the sum of the amplitudes of the individual waves) interference at point Q? (35.4)
33. In a physics lab, light with wavelength 490 nm travels in air from a laser to a photocell in 17.0 ns. When a slab of glass 0.840 m thick is placed in the light beam, with the beam incident along the normal to the parallel faces of the slab, it takes the light 21.2 ns to travel from the laser to the photocell. What is the wavelength of the light in the glass? (33.34)