Q&A Hero

Q: The intensity of sound wave A is 100 times that of sound wave B. Relative to wave B the sound level of wave A is:A) -2 dbB) +2 dbC) +10 dbD) +20 dbE) +100 db

Q: If I0= 10-12W/m2, and I= 4.5 x 10-8W/m2, what is log (I/I0)? A) 4.5 x 104 B) 18 C) 11 D) 4.7 E) 3.7

Q: The intensity of a certain sound wave is 6 W/cm2. If its intensity is raised by 10 decibels, the new intensity is:

Q: The sound level at a point P is 14 db below the sound level at a point 1.0 m from a point source. Assuming the intensity from a point source drops off like the inverse square of the distance, the distance from the source to point P is: A) 4.0 cm B) 20 m C) 2.0 m D) 5.0 m E) 25 m

Q: The sound intensity 5.0 m from point source is 0.50 W/m2. The power output of the source is: A) 12.5 W B) 39 W C) 79 W D) 160 W E) 260 W

Q: Consider two imaginary spherical surfaces of different radius, both centered on a point sound source emitting spherical waves. The power transmitted across the larger sphere is ________ the power transmitted across the smaller and the intensity at a point on the larger sphere is ________ the intensity at a point on the smaller. A) greater than, the same as B) greater than, greater than C) greater than, less than D) the same as, less than E) the same as, the same as

Q: The speed of sound in air is 340 m/s, and the density of air is 1.2 kg/m3. If the displacement amplitude of a 440-Hz sound wave is 10 m, what is the intensity of the wave? A) 0.16 W/m2 B) 0.32 W/m2 C) 12 W/m2 D) 16 W/m2 E) 32 W/m2

Q: A microphone of surface area 2.0 cm2absorbs 1.1 mW of sound. What is the intensity of sound hitting the microphone? A) 2.2 x 10-5W/m2 B) 0.55 W/m2 C) 2.2 W/m2 D) 2.8 W/m2 E) 5.5 W/m2

Q: The standard reference sound level is about: A) the threshold of human hearing at 1000 Hz B) the threshold of pain for human hearing at 1000 Hz C) the level of sound produced when the 1 kg standard mass is dropped 1 m onto a concrete floor D) the level of normal conversation E) the level of sound emitted by a standard 60 Hz tuning fork

Q: Two waves are out of phase by half a wavelength. What is this in degrees? A) 45 B) 90 C) 135 D) 180 E) 360

Q: Two waves are out of phase by half a wavelength. What is this in radians?

Q: Two sound waves are traveling through the same medium. They have the same amplitude, wavelength, and direction of travel. If the phase difference between them is 7Ï€, the type of interference they exhibit is: A) fully constructive B) fully destructive C) indeterminate D) partially constructive E) partially destructive

Q: Two small identical speakers are connected (in phase) to the same source. The speakers are 3 m apart and at ear level. An observer stands at X, 4 m in front of one speaker as shown. The sound she hears will be most intense if the wavelength is: A) 5 m B) 4 m C) 3 m D) 2 m E) 1 m

Q: Two small identical speakers are connected (in phase) to the same source. The speakers are 3 m apart and at ear level. An observer stands at X, 4 m in front of one speaker as shown. If the amplitudes are not changed, the sound he hears will be least intense if the wavelength is: A) 1 m B) 2 m C) 3 m D) 4 m E) 5 m

Q: This graph shows the position of an element of air as a function of time as a sound wave passes through it. Which letter corresponds to the period of the wave?A) AB) BC) CD) DE) E

Q: This graph shows the position of an element of air as a function of time as a sound wave passes through it. Which letter corresponds to the amplitude of the wave?A) AB) BC) CD) DE) E

Q: The speed of sound in air is 340 m/s, and the density of air is 1.2 kg/m3. If the displacement amplitude of a 440-Hz sound wave is 10 m, what is its pressure-variation amplitude? A) 1.8 Pa B) 3.3 Pa C) 11 Pa D) 15 Pa E) 28 Pa

Q: At points in a sound wave where the gas is maximally compressed, the pressure A) is a maximum B) is a minimum C) is equal to the ambient value D) is greater than the ambient value but less than the maximum E) is less than the ambient value but greater than the minimum

Q: During a time interval of exactly one period of vibration of a tuning fork, the emitted sound travels a distance: A) equal to the length of the tuning fork B) equal to twice the length of the tuning fork C) of about 330 m D) which decreases with time E) of one wavelength in air

Q: A fire whistle emits a tone of 170 Hz. Take the speed of sound in air to be 340 m/s. The wavelength of this sound is about: A) 0.5 m B) 1.0 m C) 2.0 m D) 3.0 m E) 340 m

Q: The longitudinal displacement of a mass element in a medium as a sound wave passes through it is given by . Consider a sound wave of frequency 440 Hz and wavelength 0.75m. If sm= 12 m, how long does it take an element of air to move from a displacement of 12 m to a displacement of 0 m?A) 0.57 msB) 1.1 msC) 2.3 msD) 3.4 msE) 4.6 ms

Q: The longitudinal displacement of a mass element in a medium as a sound wave passes through it is given by . Consider a sound wave of frequency 440 Hz and wavelength 0.75m. If sm= 12 m, what is the displacement of an element of air located at x = 1.2 m at time t= 0.11 s?A) 3.7 mB) 4.9 mC) 6.0 mD) 8.2 mE) 12 m

Q: Which of the following properties of a sound wave determine its "pitch"? A) amplitude B) distance form source to detector C) frequency D) phase E) speed

Q: A sound wave has a wavelength of 3.0 m. The distance from a compression center to the adjacent rarefaction center is: A) 0.75 m B) 1.5 m C) 3.0 m D) need to know wave speed E) need to know frequency

Q: Take the speed of sound to be 340 m/s. A thunder clap is heard about 3 s after the lightning is seen. The source of both light and sound is: A) moving overhead faster than the speed of sound B) emitting a much higher frequency than is heard C) emitting a much lower frequency than is heard D) about 1000 m away E) much more than 1000 m away

Q: The bulk modulus of water is 2.2 x 109Pa, and its density is 1.0 x 103kg/m3. What is the speed of sound in water? A) 1.5 x 103m/s B) 2.2 x 103m/s C) 3.5 x 103m/s D) 4.5 x 103m/s E) 2.2 x 106m/s

Q: What is a wavefront? A) A set of points on a wave that are all traveling in the same direction. B) The front of the wave is the highest point on the wave. C) The front of the wave faces the direction the wave is traveling. D) A set of points on a wave that all have the same wavelength. E) A set of points on a wave that all have the same displacement.

Q: The difference between transverse and longitudinal waves: A) depends on the frequency of the wave B) depends on the wavelength of the wave C) depends on the direction of propagation of the wave D) depends on the direction of oscillation of the medium relative to the direction of propagation of the wave E) there is no difference, they are just two ways of describing the same phenomenon

Q: The speed of a sound wave is determined by: A) its amplitude B) its intensity C) its pitch D) number of overtones present E) the transmitting medium

Q: A 40-cm long string, with one end clamped and the other free to move transversely, is vibrating in its fundamental standing wave mode. If the wave speed is 320 cm/s the frequency is: A) 32 Hz B) 16 Hz C) 8 Hz D) 4 Hz E) 2 Hz

Q: A string, clamped at its ends, vibrates in three segments. The string is 100 cm long. The wavelength is: A) 33 cm B) 67 cm C) 150 cm D) 300 cm E) need to know the frequency

Q: A 30-cm long string, with one end clamped and the other free to move transversely, is vibrating in its second harmonic. The wavelength of the constituent traveling waves is: A) 10 cm B) 30 cm C) 40 cm D) 60 cm E) 120 cm

Q: A 40-cm long string, with one end clamped and the other free to move transversely, is vibrating in its fundamental standing wave mode. The wavelength of the constituent traveling waves is: A) 10 cm B) 20 cm C) 40 cm D) 80 cm E) 160 cm

Q: Two sinusoidal waves, each of wavelength 5 m and amplitude 10 cm, travel in opposite directions on a 20-m stretched string which is clamped at each end. Excluding the nodes at the ends of the string, how many nodes appear in the resulting standing wave? A) 3 B) 4 C) 5 D) 7 E) 8

Q: A string of length Lis clamped at each end and vibrates in a standing wave pattern. The wavelengths of the constituent traveling waves CANNOT be: A) L B) 2L C) L/2 D) 2L/3 E) 4L

Q: A string of length 100 cm is held fixed at both ends and vibrates in a standing wave pattern. The wavelengths of the constituent traveling waves CANNOT be: A) 400 cm B) 200 cm C) 100 cm D) 67 cm E) 50 cm

Q: Standing waves are produced by the interference of two traveling sinusoidal waves, each of frequency 100 Hz. The distance from the 2nd node to the 5th node is 60 cm. The wavelength of each of the two original waves is: A) 50 cm B) 40 cm C) 30 cm D) 20 cm E) 15 cm

Q: A standing wave pattern is established in a string as shown. The wavelength of one of the component traveling waves is: A) 0.25 m B) 0.5 m C) 1 m D) 2 m E) 4 m

Q: If is the wavelength of the each of the component sinusoidal traveling waves that form a standing wave, the distance between adjacent nodes in the standing wave is:A) /4B) /2C) 3/4D)E) 2

Q: Two traveling waves, y1= Asin[k(x- vt)] and y2= Asin[k(x+ vt)], are superposed on the same string. The distance between the adjacent nodes is:A) vt/B) vt/2C) /2kD) /kE) 2/k

Q: A wave on a string is reflected from a fixed end. The reflected wave:A) is in phase with the original wave at the endB) is 180°out of phase with the original wave at the endC) has a larger amplitude than the original waveD) has a larger speed than the original waveE) cannot be transverse

Q: A wave on a stretched string is reflected from a fixed end P of the string. The phase difference, at P, between the incident and reflected waves is:A) 0 radB) radC)/2 radD) depends on the velocity of the waveE) depends on the frequency of the wave

Q: Which of the following represents the motion of a string element at an antinode of a standing wave?A) y= (6.0 mm)sin[(3.0 m-1)x+ (2.0 s-1)t]B) y= (6.0 mm)cos[(3.0 m-1)x" (2.0 s-1)t]C) y= (6.0 mm)cos[(3.0 m-1)x+ (2.0 s-1)t]D) y= (6.0 mm)sin[(3.0 m-1)xE) y= (6.0 mm)cos[(2.0 s-1)t

Q: Which of the following represents a standing wave?

Q: When a string is vibrating in a standing wave pattern the power transmitted across an antinode, compared to the power transmitted across a node, is: A) more B) less C) the same (zero) D) the same (non-zero) E) sometimes more, sometimes less, and sometimes the same

Q: When a certain string is clamped at both ends, the lowest four resonant frequencies are measured to be 100, 150, 200, and 250 Hz. One of the resonant frequencies (below 200 Hz) is missing. What is it? A) 25 Hz B) 50 Hz C) 75 Hz D) 125 Hz E) 225 Hz

Q: When a certain string is clamped at both ends, the lowest four resonant frequencies are 50, 100, 150, and 200 Hz. When the string is also clamped at its midpoint, the lowest four resonant frequencies are: A) 50, 100, 150, and 200 Hz B) 50, 150, 250, and 300 Hz C) 100, 200, 300, and 400 Hz D) 25, 50 75, and 100 Hz E) 75, 150, 225, and 300 Hz

Q: A standing wave: A) can be constructed from two similar waves traveling in opposite directions B) must be transverse C) must be longitudinal D) has motionless points that are closer than half a wavelength E) has a wave velocity that differs by a factor of two from what it would be for a traveling wave

Q: The sinusoidal waveis incident on the fixed end of a string at x= L. The reflected wave is given by:

Q: Two sinusoidal waves travel along the same string. They have the same wavelength and frequency. Their amplitudes are ym1= 2.5 mm and ym2= 4.5 mm, and their phases are /4 rad and /2 rad, respectively. What are the amplitude and phase of the resultant wave?A) cannot solve without knowing the wavelengthB) 5.1 mm, 0.51 radC) 5.1 mm, 0.79 radD) 6.5 mm, 1.3 radE) 7.0 mm, 1.3 rad

Q: Two sources, S1and S2, each emit waves of wavelength in the same medium. The phase difference between the two waves, at the point P shown, is . The quantity is:A) the distance S1S2B) the angle S1PS2C) /2D) the phase difference between the two sourcesE) zero for transverse waves, for longitudinal waves

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Q: Two sinusoidal waves travel in the same direction and have the same frequency. Their amplitudes are y1mand y2m. The smallest possible amplitude of the resultant wave is:

Q: Fully destructive interference between two sinusoidal waves of the same frequency and amplitude occurs only if they:A) travel in the same direction and are 270°out of phaseB) travel in the same direction and are 45°out of phaseC) travel in the same direction and are in phaseD) travel in the same direction and are 180°out of phaseE) travel in the same direction and are 90°out of phase

Q: Fully constructive interference between two sinusoidal waves of the same frequency occurs only if they:A) travel in the same direction and are 270°out of phaseB) travel in the same direction and are 45°out of phaseC) travel in the same direction and are in phaseD) travel in the same direction and are 180°out of phaseE) travel in the same direction and are 90°out of phase

Q: Two sinusoidal waves have the same angular frequency, the same amplitude ym, and travel in the same direction in the same medium. If they differ in phase by 50°, the amplitude of the resultant wave is given byA) 0.64ymB) 1.3 ymC) 0.91ymD) 1.8 ymE) 0.35 ym

Q: Two traveling sinusoidal waves interfere to produce a wave with the mathematical form

Q: The sum of two sinusoidal traveling waves is a sinusoidal traveling wave only if: A) their amplitudes are the same and they travel in the same direction B) their amplitudes are the same and they travel in opposite directions C) their frequencies are the same and they travel in the same direction D) their frequencies are the same and they travel in opposite directions E) their frequencies are the same and their amplitudes are the same

Q: The displacement of an element of a string is given by , with x in meters and tin seconds. Given that , what is v?A) 0.065 m/sB) 0.25 m/sC) 2.0 m/sD) 3.9 m/sE) 15 m/s

Q: A sinusoidal wave is generated by moving the end of a string up and down periodically. The generator does not supply any power when the end of the string A) has its least acceleration B) has its greatest displacement C) has half its greatest displacement D) has one fourth its greatest displacement E) has its least displacement

Q: A sinusoidal wave is generated by moving the end of a string up and down periodically. The generator must supply the greatest power when the end of the string: A) has its greatest acceleration B) has its greatest displacement C) has half its greatest displacement D) has one fourth its greatest displacement E) has its least displacement

Q: Two identical but separate strings, with the same tension, carry sinusoidal waves with the same frequency. Wave A has an amplitude that is twice that of wave B and transmits energy at a rate that is __________ that of wave B. A) half B) twice C) one-fourth D) four times E) eight times

Q: Two identical but separate strings, with the same tension, carry sinusoidal waves with the same amplitude. Wave A has a frequency that is twice that of wave B and transmits energy at a rate that is __________ that of wave B. A) half B) twice C) one-fourth D) four times E) eight times

Q: A stretched string, clamped at its ends, vibrates at a particular frequency. To double that frequency, one can change the string tension by a factor of: A) 2 B) 4 C) D) 1/2 E)

Q: A long string is constructed by joining the ends of two shorter strings. The tension in the strings is the same but string I has 4 times the linear mass density of string II. When a sinusoidal wave passes from string I to string II: A) the frequency decreases by a factor of 4 B) the frequency decreases by a factor of 2 C) the wave speed decreases by a factor of 4 D) the wave speed decreases by a factor of 2 E) the wave speed increases by a factor of 2

Q: Three separate strings are made of the same material. String 1 has length Land tension , string 2 has length 2Land tension 2and string 3 has length 3Land tension 3. A pulse is started at one end of each string. If the pulses start at the same time, the order in which they reach the other end is:A) 1, 2, 3B) 3, 2, 1C) 2, 3, 1D) 3, 1, 2E) they all take the same time

Q: When a 100-Hz oscillator is used to generate a sinusoidal wave on a certain string the wavelength is 10 cm. When the tension in the string is doubled the generator produces a wave with a frequency and wavelength of: A) 200 Hz and 20 cm B) 141 Hz and 10 cm C) 100 Hz and 20 cm D) 100 Hz and 14 cm E) 50 Hz and 14 cm

Q: The tension in a string with a linear density of 0.0010 kg/m is 0.40 N. A 100 Hz sinusoidal wave on this string has a wavelength of: A) 0.20 cm B) 2.0 cm C) 5.0 cm D) 20 cm E) 400 cm

Q: The diagram shows three identical strings that have been put under tension by suspending masses of 5 kg each. For which is the wave speed the greatest? A) 1 B) 2 C) 3 D) 1 and 3 tie E) 2 and 3 tie

Q: The time required for a small pulse to travel from A to B on a stretched cord shown is NOT altered by changing: A) the linear mass density of the cord B) the length between A and B C) the shape of the pulse D) the tension in the cord E) none of the above (changes in all alter the time)

Q: The speed of a sinusoidal wave on a string depends on: A) the frequency of the wave B) the wavelength of the wave C) the length of the string D) the tension in the string E) the amplitude of the wave

Q: Sinusoidal waves travel on five identical strings. Four of the strings have the same tension, but the fifth has a different tension. Use the mathematical forms of the waves, gives below, to identify the string with the different tension. In the expressions given below xand yare in centimeters and tis in seconds.A) y(x,t) = (2 cm) sin (2x- 4t)B) y(x,t) = (2 cm) sin (4x- 10t)C) y(x,t) = (2 cm) sin (6x- 12t)D) y(x,t) = (2 cm) sin (8x- 16t)E) y(x,t) = (2 cm) sin (10x- 20t)

Q: A transverse wave travels on a string of length 1.3 m and diameter 1.1 mm, whose mass is 10 g and which is under a tension of 16 N. What is the linear mass density of the string? A) 7.7 x 10-3kg/m B) 0.13 kg/m C) 7.7 kg/m D) 46 kg/m E) 130 kg/m

Q: In the figure, a wave is traveling from left to right. If the point marked "D" represents the origin at time t= 0, and the displacement of the wave is given by , what is the phase constant

Q: A transverse traveling sinusoidal wave on a string has a frequency of 100 Hz, a wavelength of 0.040 m and an amplitude of 2.0 mm. The maximum acceleration of any point on the string is: A) 0 m/s2 B) 200 m/s2 C) 390 m/s2 D) 790 m/s2 E) 1600 m/s2

Q: A transverse traveling sinusoidal wave on a string has a frequency of 100 Hz, a wavelength of 0.040 m and an amplitude of 2.0 mm. The maximum velocity of any point on the string is: A) 0.20m/s B) 1.3 m/s C) 4.0m/s D) 15 m/s E) 25 m/s

Q: A string carries a sinusoidal wave with an amplitude of 2.0 cm and a frequency of 100 Hz. The maximum speed of any point on the string is: A) 2.0 m/s B) 4.0 m/s C) 6.3 m/s D) 13 m/s E) unknown (not enough information is given)

Q: Suppose the maximum speed of a string carrying a sinusoidal wave is vs. When the displacement of a point on the string is half its maximum, the speed of the point is: A) vs/2 B) 2vs C) vs/4 D) 3vs/4 E) vs/2

Q: The mathematical forms for the three sinusoidal traveling waves are given bywave 1: y(x,t) = (2 cm) sin (3x- 6t)wave 2: y(x,t) = (3 cm) sin (4x-12t)wave 3: y(x,t) = (4 cm) sin (5x- 11t)where xis in meters and t is in seconds. Of these waves:A) wave 1 has the greatest wave speed and the greatest maximum transverse string speedB) wave 2 has the greatest wave speed and wave 1 has the greatest maximum transverse string speedC) wave 3 has the greatest wave speed and the greatest maximum transverse string speedD) wave 2 has the greatest wave speed and wave 3 has the greatest maximum transverse string speedE) wave 3 has the greatest wave speed and wave 2 has the greatest maximum transverse string speed