A string on a guitar is plucked. If, at this instant, someone touches this guitar string at its center, at which of its harmonics given below would the string be able to vibrate?<--EndFragment--> sity?
1.at the first harmonic only
2.at the first and third harmonics
3.at the second and fourth harmonics
4.at the first and second harmonics
[Ques. 2] Within a standing wave on a string,
1.all points along the string that oscillate do so within a range of different frequencies and amplitudes.
2.all points along the string that oscillate do so at the same frequency but within a range of different amplitudes.
3.all points along the string that oscillate do so within a range of different frequencies but at the same amplitude.
4.all points along the string that oscillate do so at the same frequency and amplitude.
[Ques. 3] When a standing wave occurs on a string,
1.all points along the string move up and down equal distances.
2.all points along the string move up and down, but some move more than others.
3.many points along the string move up and down, some move more than others, and some are stationary.
4.all points along the string are completely stationary because the waves from each direction cancel each other out.
[Ques. 4] The concept of superposition implies that (choose the best answer)
1.when two waves that both have positive displacements cross each others' paths, the resulting wave will also have a positive displacement.
2.when two waves cross that are identical, except that one has a positive displacement and the other a negative displacement, they will cancel each other out at that point in space and time.
3.two traveling waves can pass through each other without being altered.
4.all of these are true.
[Ques. 5] A sound source is placed in the center of a very wide and long room that has a low ceiling. Assume that the ceiling and floor are constructed of a material that absorbs the sound completely. In this situation, how would the intensity of the sound heard vary if a person moves from a distance of 10 meters from the source to a distance of 20 meters from the source?
1.The sound would have about the intensity 20 m from the source that it has 10 m from the source.
2.The sound would have about the intensity 20 m from the source that it has 10 m from the source.
3.The sound would have about the same intensity 20 m from the source that it has 10 m from the source.
4.The sound would have about twice the intensity 20 m from the source that it has 10 m from the source.
[Ques. 6] A ringing alarm clock is placed in a bell jar, which is then sealed, and the air is pumped out of it. Which effect will most likely occur?
1.The sound of the ringing alarm clock will get louder as the air is pumped out.
2.The sound of the ringing alarm clock will get softer as the air is pumped out.
3.No noticeable change will occur as the air is pumped out.
4.The sound will diminish completely immediately after the air has begun to be pumped out.
[Ques. 7] Let's say that you are spinning a fixed-frequency buzzer attached to a string in a circular path around you at a constant speed. The frequency that you hear as you spin the buzzer<--EndFragment--> sity?
1.is greater than the frequency of the buzzer and it is constant.
2.alternates between being greater than the frequency of the buzzer and less than the frequency of the buzzer.
3.is less than the frequency of the buzzer and it is constant.
4.is the same as the frequency of the buzzer.
[Ques. 8] If a rock concert has a sound level of 120 dB associated with it and a cheering crowd has a sound level of 90 dB associated with it, how many times greater is the rock concert's intensity compared to the cheering crowd's intensity?
1.30
2.90
3.300
4.1000
[Ques. 9] Let's say that a loud pulse is emitted from a point on the surface of the Earth in all directions. Who would hear the sound first, someone located one km away horizontally, or someone located on a mountain top one km above the location of the sound source? Note that air is cooler at higher elevations.
1.the person located one km away horizontally
2.the person located one km away vertically
3.They would both hear the sound at the same instant.
4.There is not enough information available to determine this.
[Ques. 10] If the wavelength of sound is increased by a factor of 3, what happens to its speed and frequency?
1.Its speed increases by a factor of 3, and so does its frequency.
2.Its frequency increases by a factor of 3, but the speed stays the same.
3.Its frequency decreases by a factor of 3, but its speed stays the same.
4.Its speed decreases by a factor of 3, and so does its frequency.
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