Question 1

An pipe of length L that is open at both ends is resonating at its fundamental frequency. Which statement about the sound is correct?

Accepted Answer

For a pipe open at both ends, the fundamental frequency has a wavelength of 2L, with displacement nodes at both ends and an antinode at the midpoint.

Question 2

You double your distance from a sound source that is radiating equally in all directions. What happens to the intensity of the sound? It reduces to

Accepted Answer

The intensity of sound follows the inverse square law, meaning if you double the distance from the source, the intensity of the sound reduces to one-fourth its original value.

Question 3

An organ pipe of length L that is open at one end resonates in its third harmonic with a wavelength of 2L/3. Is the other end of the pipe closed or open?

Accepted Answer

The answer of An organ pipe of length L that...

Question 4

Oxygen molecules are 16 times more massive than hydrogen molecules. At a given temperature, the average molecular kinetic energy of oxygen molecules, compared to that of hydrogen
Molecules,

Accepted Answer

The average molecular kinetic energy of a gas at a given temperature is the same for all gases, regardless of the molecular mass, according to the kinetic theory of gases. This is because the kinetic energy is directly proportional to the temperature (in Kelvin).

Question 5

In a resonating pipe that is open at both ends, there

Accepted Answer

In a resonating pipe that is open at both ends, there are displacement antinodes at each end because the air at the open ends can move freely, creating maximum displacement at these points.

Question 6

Suppose that a sound source is emitting waves uniformly in all directions. If you move to a point twice as far away from the source, the frequency of the sound will be

Accepted Answer

The frequency of a sound wave depends on the source of the sound and does not change as you move closer to or further from the source. Distance affects the intensity or loudness of the sound, not its frequency.

Question 7

Consider a pipe of length L that is open at both ends. What are the wavelengths of the three lowest-pitch tones produced by this pipe?

Accepted Answer

The wavelengths of the three lowest-pitch tones produced by a pipe open at both ends are given by the formula $2L/n$, where $n$ is an odd integer starting from 1. Thus, the first three wavelengths are $2L/1 = 2L$, $2L/3$, and $2L/5$. However, none of the provided options correctly matches this sequence, indicating a mistake in my explanation. Reevaluating, the correct sequence for a pipe open at both ends should actually be the fundamental frequency ($2L$), followed by the second harmonic ($L$), and then the third harmonic ($2L/3$), which correctly matches option D.

Question 8

Consider a pipe of length L that is open at one end and closed at the other end. What are the wavelengths of the three lowest-pitch tones produced by this pipe?

Accepted Answer

For a pipe open at one end and closed at the other, the wavelengths of the harmonics are given by 4L/n, where n is an odd integer (1, 3, 5,...). Thus, the wavelengths of the three lowest-pitch tones are 4L (n=1), 4L/3 (n=3), and 4L/5 (n=5).

Question 9

The lowest tone to resonate in a pipe of length L that is closed at one end but open at the other end is 200 Hz. Which one of the following frequencies will not resonate in that pipe?

Accepted Answer

The answer of The lowest tone to resonate in a...

Question 10

What characteristics of a sound wave are related to the "pitch" of a musical note? (There could be more than one correct choice.)

Accepted Answer

The pitch of a musical note is primarily related to the frequency of the sound wave, as higher frequencies correspond to higher pitches. The period and wavelength are also related to frequency, as they are inversely proportional to it. Amplitude is related to loudness, not pitch.

Question 11

A pipe of length L that is closed at one end and open at the other end is resonating at its fundamental frequency. Which statement about the sound is correct?

Accepted Answer

In a pipe closed at one end and open at the other, the fundamental frequency has a wavelength of 4L, with a displacement node at the closed end and a displacement antinode at the open end.

Question 12

Sound A has a high pitch and sound B has a low pitch. Which of the following statements about these two sounds are correct? (There could be more than one correct choice.)

Accepted Answer

The frequency of a sound is related to its pitch; a higher pitch means a higher frequency, so sound A has a greater frequency than sound B. The period is the inverse of frequency, so a higher frequency (sound A) means a shorter period compared to a lower frequency (sound B).

Question 13

Seven seconds after a brilliant flash of lightning, thunder shakes the house. Approximately how far was the lightning strike from the house?

Accepted Answer

Sound travels through air at approximately 343 meters per second. Since thunder is heard 7 seconds after seeing lightning, the distance can be calculated as 343 meters/second * 7 seconds = 2401 meters, which is about 2.4 kilometers, making the answer approximately 2 kilometers away.

Question 14

A fixed container holds oxygen and helium gases at the same temperature. Which of the following statements are correct? (There could be more than one correct choice.)

Accepted Answer

At the same temperature, all gases have the same average kinetic energy due to the kinetic theory of gases, which explains choice E. However, because helium atoms are lighter than oxygen molecules, they move faster to maintain the same kinetic energy, which explains choice D.

Question 15

In a resonating pipe that is open at one end and closed at the other, there

Accepted Answer

In a resonating pipe that is open at one end and closed at the other, there is a displacement node at the closed end because the air cannot move freely, and a displacement antinode at the open end because the air can move freely.

Question 16

Consider the standing wave on a guitar string and the sound wave generated by the string as a result of this vibration. What do these two waves have in common? (There may be more than one
Correct choice.)

Accepted Answer

Both the standing wave on the string and the sound wave generated have the same period and frequency, as the frequency of vibration of the string determines the frequency of the sound wave produced.

Question 17

The lowest tone to resonate in pipe of length L that is open at both ends is 200 Hz. Which one of the following frequencies will not resonate in the same pipe?

Accepted Answer

A pipe open at both ends resonates at frequencies that are multiples of the fundamental frequency. The fundamental frequency here is 200 Hz, so it will resonate at 200 Hz, 400 Hz (2x200 Hz), 600 Hz (3x200 Hz), and 800 Hz (4x200 Hz). 900 Hz is not a multiple of 200 Hz, so it will not resonate in the pipe.

Question 18

In a resonating pipe that is open at one end and closed at the other end, there

Accepted Answer

In a resonating pipe that is open at one end and closed at the other, the closed end must have a displacement node because the air cannot move at the boundary, and the open end must have a displacement antinode because the air can move freely there.

Question 19

The absolute temperature of an ideal gas is directly proportional to which of the following quantities?

Accepted Answer

The absolute temperature of an ideal gas is directly proportional to the average kinetic energy of its molecules, according to the kinetic theory of gases. This relationship is described by the equation $KE = \frac{3}{2}kT$, where $KE$ is the average kinetic energy of the molecules, $k$ is the Boltzmann constant, and $T$ is the temperature in Kelvin. The other options do not have a direct proportional relationship with the absolute temperature.

Question 20

A mole of diatomic oxygen molecules and a mole of diatomic nitrogen molecules are at STP. Which statements are true about these molecules? (There could be more than one correct choice.)

Accepted Answer

At STP, all gases have the same average kinetic energy per molecule due to the equipartition theorem, and a mole of any substance contains the same number of entities, defined by Avogadro's number.

Quiz 2: Describing Motion: Kinematics in One Dimension