waves and sound

Question 1

it is a raveling disturbance that carries energy from one place to another.

Answer 1

wave

Question 2

Does a wave move objects from place to place?

Answer 2

No, waves carry energy, not objects.

Question 3

A wave where the disturbance moves parallel to the wave’s direction.

Answer 3

longitudinal wave
- a sound wave is a longitudinal wave
- particles move back and forth in the same direction as the waves traves

Question 4

A wave where the disturbance moves perpendicular to the wave’s direction.

Answer 4

transverse wave
- examples: light waves, radio waves, microwave and waves on guitar string
- particles move up and down, perpendicular to the direction the wave travels

Question 5

Waves that repeat cycles or patterns over and over, like rhythmic slinky waves.

Answer 5

periodic waves
- formed when the source moves in simple harmonic motion
- back and forth repetitive movement where displacement on both sides of a central position
- example: swinging pendulum or a vibrating slinky.

Question 6

what happens to each part of a slinky in a periodic wave?

Answer 6

Each segment vibrates in simple harmonic motion.

Question 7

A wave that looks like it’s not moving, formed when two waves traveling in opposite directions combine.

Answer 7

standing wave
- formed by the superposition of two waves with the same frequency, amplitude, and direction.

Question 8

A point on a standing wave with maximum oscillation.

Answer 8

antinode

Question 9

A point on a standing wave with zero oscillation that appears fixed.

Answer 9

node

Question 10

How can you create a standing wave?

Answer 10

Use a traveling wave and its reflection to ensure they combine with the same frequency and amplitude.

Question 11

A is the maximum excursion of a particle of the medium from the particles undisturbed position.

Answer 11

amplitude

Question 12

it is the horizontal length of one cycle of the wave.
10

Answer 12

wavelength

Question 13

it is the time required for one complete cycle.

Answer 13

period

Question 14

it is related to the period and has units of Hz, or s-1

Answer 14

frequency

Question 15

What is the relationship between speed, wavelength, and frequency?

Answer 15

Speed = Wavelength × Frequency

Question 16

What determines the speed of a wave on a string?

Answer 16

How quickly a particle of the string is accelerated upward by the pulling force.

Question 17

What causes upward acceleration in a string wave?

Answer 17

The net pulling force acting on the string.

Question 18

A longitudinal wave created by vibrating objects, moving through a medium.

Answer 18

sound

Question 19

Can sound travel in a vacuum?

Answer 19

No, sound needs a medium like air, liquid, or solid to travel.

Question 20

condensations vs rarefactions

Answer 20

condensations:
areas where particles are close together

rarefactions:
are where particles are spread apart in a sound wave.

Question 21

hat happens to air molecules in a sound wave?

Answer 21

They vibrate back and forth but do not travel with the wave.

Question 22

What is the wavelength of a sound wave?

Answer 22

The distance between two adjacent condensations or rarefactions.

Question 23

it is the number of cycles per second.

Answer 23

frequency

Question 24

A sound with a single frequency

Answer 24

pure tone

Question 25

The brain interprets the frequency in terms of the subjective quality

Answer 25

pitch

Question 26

it is an attribute of a sound that depends primarily on the pressure amplitude of the wave

Answer 26

loudness

Question 27

true or false:
Sound travels through gases, liquids, and solids at considerably different speeds.

Answer 27

true

Question 28

the power passing through a surface divided by the area of that surface.

Answer 28

sound intensity

Question 29

How does sound intensity change with the area?

Answer 29

The smaller the area, the higher the intensity; the larger the area, the lower the intensity.

Question 30

What happens to the intensity of sound if the energy is spread over a large area?

Answer 30

The intensity is lower (the sound is quieter).

Question 31

The amount of energy transported by the sound wave per second.

Answer 31

power of a wave sound

Question 32

What is the threshold of hearing?

Answer 32

The smallest sound intensity that the human ear can detect, about
1×10 ^−12 W/m² for a 1000 Hz tone.

Question 33

At what intensity can sound become painful to hear?

Answer 33

Continuous exposure to intensities greater than 1 W/m² can be painful.

Question 34

How does distance from the sound source affect intensity?

Answer 34

The intensity decreases as you move farther from the source.

Question 35

How is sound emitted from a source in terms of intensity?

Answer 35

sound is emitted uniformly in all directions, so the intensity depends on the distance from the source.

Question 36

What is the unit used to measure sound intensity?

Answer 36

the decibel (dB) is used to measure and compare sound intensities

Question 37

What is the formula for intensity level in decibels?

Answer 37

index card

Question 38

What happens when the intensity of a sound equals 𝐼0?

Answer 38

The intensity level is zero because
log(1)=0

Question 39

Why is the decibel scale logarithmic?

Answer 39

The human ear responds to sound intensity in a way that is better represented on a logarithmic scale.

Question 40

the change in frequency or pitch of sound due to the motion of the sound source or observer.

Answer 40

Doppler Effect

Question 41

What happens to the pitch of an ambulance siren as it moves toward you?

Answer 41

The pitch gets higher as it approaches and lower as it moves away.

Question 42

How does ultrasound help in medicine?

Answer 42

Ultrasound uses sound waves to create images and also to treat tumors by vibrating at high frequencies.

Question 43

It measures changes in sound frequency as the sound bounces off moving objects like red blood cells, helping doctors track blood flow.

Answer 43

Doppler ultrasound

Question 44

How does sound help break apart tumors in medicine?

Answer 44

Ultrasonic waves vibrate at 23 kHz, which can shatter parts of a tumor when directed at it.