Question 1

At a rock concert, if the speakers are placed on the floor instead of higher up on a tower, state if the intensity of the sound you would hear, from the same distance away, is the same or different and why.

Accepted Answer

Intensity would increase due to reflections off floor.

Question 2

What man-made object exceeded the speed of sound long before the invention of the airplane or the bullet?

Accepted Answer

A "cracked whip" creates a sonic boom.

Question 3

Which of the following is a false statement?

Accepted Answer

Sound requires a medium (solid, liquid, or gas) to travel through, and it cannot propagate through a vacuum because there are no molecules to transmit the sound waves.

Question 4

Sound vibrations with frequencies less than 20 Hz are called

Accepted Answer

Sound vibrations with frequencies less than 20 Hz are referred to as infrasonics. These are below the normal human hearing range, which typically ranges from 20 Hz to 20 kHz.

Question 5

Sound vibrations with frequencies greater than 20,000 Hz are called

Accepted Answer

Sound vibrations with frequencies greater than 20,000 Hz are referred to as ultrasonics. This range is above the upper limit of human hearing, which typically caps at around 20 kHz.

Question 6

As atmospheric pressure increases, what happens to the velocity of sound? (Assume that all other factors remain constant.)

Accepted Answer

The velocity of sound in air is primarily determined by the temperature of the air, not by the atmospheric pressure. Therefore, changes in atmospheric pressure, assuming all other factors (especially temperature) remain constant, do not affect the velocity of sound.

Question 7

If you were to inhale a few breaths from a helium gas balloon, you would probably experience an amusing change in your voice. You would sound like Donald Duck or Alvin the Chipmunk. What is the cause of this curious high-pitched effect?

Accepted Answer

Sound travels faster in helium than in air, which increases the speed of sound waves and results in a higher frequency, making your voice sound higher-pitched.

Question 8

What happens to the velocity of sound in a gas when the absolute temperature of that gas is doubled?

Accepted Answer

The velocity of sound in a gas is proportional to the square root of the temperature. When the temperature is doubled, the velocity increases by the square root of 2, which is approximately 1.41 times its original value.

Question 9

Since the Helium molecule (He) is 2 times as massive as the Hydrogen molecule (H₂), the speed of sound in Hydrogen is ________ the speed in Helium.

Accepted Answer

The answer of Since the Helium molecule (He) is 2...

Question 10

The decibel level of sound is related to its

Accepted Answer

The decibel level of a sound is a measure of its intensity, which is the power carried by sound waves per unit area. This is different from pitch, velocity, frequency, and wavelength, which relate to other characteristics of sound.

Question 11

The intensity of a sound wave is proportional to its

Accepted Answer

The intensity of a sound wave is directly proportional to its power. Intensity is a measure of the power per unit area, where the power is the rate at which energy is transferred by the wave.

Question 12

If the intensity of sound changes (increases) by a factor of 100, the decibel level changes by a factor of

Accepted Answer

The decibel level change is calculated using the formula 10 * log10(I2/I1), where I2/I1 is the intensity ratio. For a 100 times increase, log10(100) = 2, so the change is 10 * 2 = 20 dB.

Question 13

When sound passes from air into water

Accepted Answer

The frequency of a sound wave remains constant when transitioning between mediums because it is determined by the source of the sound, not the medium through which it travels. The velocity and wavelength of sound, however, can change depending on the properties of the medium (such as density and elasticity).

Question 14

Two coherent sound waves will destructively interfere when the path difference is the wavelength times what?

Accepted Answer

Destructive interference occurs when the path difference between two coherent sound waves is half the wavelength times an odd integer, leading to the waves being out of phase and canceling each other out.

Question 15

Two coherent sound waves will constructively interfere when the path difference is the wavelength times what?

Accepted Answer

Constructive interference occurs when the path difference between two coherent sound waves is an integer multiple of the wavelength. This means the waves are in phase at the point of superposition, resulting in a maximum amplitude of the resultant wave.

Question 16

If the phase angle between sound waves from two different point sources is 180°, what kind of interference will occur?

Accepted Answer

When the phase angle between sound waves from two different point sources is 180°, it means the waves are out of phase, leading to destructive interference. This results in the waves canceling each other out to some extent.

Question 17

Consider the standing wave on a guitar string and the sound wave generated by the guitar as a result of this vibration. What do these two waves have in common?

Accepted Answer

The standing wave on a guitar string and the sound wave it generates share the same frequency. The frequency of the vibration of the string determines the pitch of the sound heard, and this frequency is the same for both the standing wave on the string and the sound wave produced in the air.

Question 18

In order to produce beats, the two sound waves should have

Accepted Answer

Beats are produced when two sound waves of slightly different frequencies interfere with each other. This results in a variation in the amplitude of the sound heard, creating the characteristic "wah-wah" effect of beats.

Question 19

An unknown tuning fork is sounded along with a tuning fork whose frequency is 256. Hz and a beat frequency of 3. Hz is heard. What is the frequency of the unknown tuning fork?

Accepted Answer

The beat frequency is the absolute difference between the frequencies of two sounds. Since the beat frequency is 3 Hz, the unknown tuning fork could have a frequency either 3 Hz higher or 3 Hz lower than 256 Hz, making it either 253 Hz or 259 Hz.

Question 20

The change in the frequency of a wave due to the motion of the source (or observer) is known as

Accepted Answer

The Doppler effect describes the change in frequency of a wave in relation to an observer who is moving relative to the wave source. It is commonly observed with sound waves, but it also applies to electromagnetic waves such as light.

Quiz 14: Sound

At a rock concert, if the speakers are placed on the floor instead of higher up on a tower, state if the intensity of the sound you would hear, from the same distance away, is the same or different and why.

What man-made object exceeded the speed of sound long before the invention of the airplane or the bullet?

Which of the following is a false statement?

Sound vibrations with frequencies less than 20 Hz are called

Sound vibrations with frequencies greater than 20,000 Hz are called

As atmospheric pressure increases, what happens to the velocity of sound? (Assume that all other factors remain constant.)

If you were to inhale a few breaths from a helium gas balloon, you would probably experience an amusing change in your voice. You would sound like Donald Duck or Alvin the Chipmunk. What is the cause of this curious high-pitched effect?

What happens to the velocity of sound in a gas when the absolute temperature of that gas is doubled?

Since the Helium molecule (He) is 2 times as massive as the Hydrogen molecule (H₂) , the speed of sound in Hydrogen is ________ the speed in Helium.

The decibel level of sound is related to its

The intensity of a sound wave is proportional to its

If the intensity of sound changes (increases) by a factor of 100, the decibel level changes by a factor of

When sound passes from air into water

Two coherent sound waves will destructively interfere when the path difference is the wavelength times what?

Two coherent sound waves will constructively interfere when the path difference is the wavelength times what?

If the phase angle between sound waves from two different point sources is 180°, what kind of interference will occur?

Consider the standing wave on a guitar string and the sound wave generated by the guitar as a result of this vibration. What do these two waves have in common?

In order to produce beats, the two sound waves should have

An unknown tuning fork is sounded along with a tuning fork whose frequency is 256. Hz and a beat frequency of 3. Hz is heard. What is the frequency of the unknown tuning fork?

The change in the frequency of a wave due to the motion of the source (or observer) is known as

Quiz 14: Sound

At a rock concert, if the speakers are placed on the floor instead of higher up on a tower, state if the intensity of the sound you would hear, from the same distance away, is the same or different and why.

What man-made object exceeded the speed of sound long before the invention of the airplane or the bullet?

Which of the following is a false statement?

Sound vibrations with frequencies less than 20 Hz are called

Sound vibrations with frequencies greater than 20,000 Hz are called

As atmospheric pressure increases, what happens to the velocity of sound? (Assume that all other factors remain constant.)

If you were to inhale a few breaths from a helium gas balloon, you would probably experience an amusing change in your voice. You would sound like Donald Duck or Alvin the Chipmunk. What is the cause of this curious high-pitched effect?

What happens to the velocity of sound in a gas when the absolute temperature of that gas is doubled?

Since the Helium molecule (He) is 2 times as massive as the Hydrogen molecule (H2) , the speed of sound in Hydrogen is ________ the speed in Helium.

The decibel level of sound is related to its

The intensity of a sound wave is proportional to its

If the intensity of sound changes (increases) by a factor of 100, the decibel level changes by a factor of

When sound passes from air into water

Two coherent sound waves will destructively interfere when the path difference is the wavelength times what?

Two coherent sound waves will constructively interfere when the path difference is the wavelength times what?

If the phase angle between sound waves from two different point sources is 180°, what kind of interference will occur?

Consider the standing wave on a guitar string and the sound wave generated by the guitar as a result of this vibration. What do these two waves have in common?

In order to produce beats, the two sound waves should have

An unknown tuning fork is sounded along with a tuning fork whose frequency is 256. Hz and a beat frequency of 3. Hz is heard. What is the frequency of the unknown tuning fork?

The change in the frequency of a wave due to the motion of the source (or observer) is known as

Since the Helium molecule (He) is 2 times as massive as the Hydrogen molecule (H₂) , the speed of sound in Hydrogen is ________ the speed in Helium.