Vibrations and Sound

Question 1

What type of a wave is a soundwave?

Answer 1

Soundwaves are longitudinal waves

Question 2

Does sound require a medium? How do you prove this?

Answer 2

Sound does require a medium, proved by the bell jar experiment

Question 3

What is sound measured in?

Answer 3

Hertz (Hz)

Question 4

How would you demonstrate sound interference? How would you prove sound is a wave?

Answer 4

Walking beside two speakers or rotating a tuning fork

Question 5

What is the audible sound for humans?

Answer 5

20Hz to 20,000Hz

Question 6

What affects the speed of sound?

Answer 6

1. The elastic property of the substance
2. The density of a substance
3. Temperature

Question 7

What are the characteristics of notes?

Answer 7

1. Pitch
2. Loudness
3. Quality

Question 8

What defines the pitch of a note?

Answer 8

Its frequency

Question 9

What defines the loudness of a note?

Answer 9

Its amplitude

Question 10

What defines the quality of a note?

Answer 10

The relative strength and number of overtones present

Question 11

What are overtones?

Answer 11

They are integer multiples of the fundamental frequency, starting at 2f

Question 12

What are harmonics?

Answer 12

They are integer multiples of the fundamental frequency, starting at f

Question 13

What are very high frequencies called?

Answer 13

Ultrasonic (Heard by dogs and bats)

Question 14

What are very low frequencies called?

Answer 14

Infrasonic (“Felt” by horses)

Question 15

What is sound intensity level?

Answer 15

The scale adjusted to human hearing measured in decibels (dB)

Question 16

1. A 3dB rise in sound would mean…
2. A 6dB rise in sound would mean…

Answer 16

1. Sound intensity level would double
2. Sound intensity level would multiply by 4

Question 17

What is the intensity of a sound?

Answer 17

The rate of sound energy incident on 1m² at a right angle to the direction of the motion of the sound, Wm-²

Question 18

What is the threshold of hearing?

Answer 18

1×10-¹²Wm-²

Question 19

What is resonance?

Answer 19

The transfer of energy between two bodies with the same natural frequency

Question 20

How would you demonstrate resonance?

Answer 20

You would use Barton’s pendulum

Question 21

State 3 examples of resonance.

Answer 21

1. Pushing someone on a swing
2. Breaking a wine glass with sound
3. Vocal chords

Question 22

What is the human ear resonant frequency?

Answer 22

2,000Hz to 4,000Hz

Question 23

What occurs at maximum amplitude?

Answer 23

An antinode

Question 24

What occurs at minimum amplitude?

Answer 24

A node

Question 25

To verify the inverse proportionality of length and frequency you would use...

Answer 25

A sonometer

Question 26

Explain open pipe harmonics.

Answer 26

There are antinodes at both ends and they can produce all harmonics

Question 27

Explain closed pipe harmonics.

Answer 27

There is a node at the closed end and an antinode at the open end, they can produce odd harmonics only

Question 28

When calculating the speed of sound in a closed pipe, why is the diameter multiplied by 0.3?

Answer 28

The antinode at the open end actually happens a small distance outside the pipe, this is the correction factor which is calculated by multiplying the internal diameter by 0.33

Question 28

When calculating the speed of sound in a closed pipe, why is the diameter multiplied by 0.3?

Answer 28

The antinode at the open end actually happens a small distance outside the pipe, this is the correction factor which is calculated by multiplying the internal diameter by 0.33

Question 28

When calculating the speed of sound in a closed pipe, why is the diameter multiplied by 0.3?

Answer 28

The antinode at the open end actually happens a small distance outside the pipe, this is the correction factor which is calculated by multiplying the internal diameter by 0.33

Question 28

When calculating the speed of sound in a closed pipe, why is the diameter multiplied by 0.3?

Answer 28

The antinode at the open end actually happens a small distance outside the pipe, this is the correction factor which is calculated by multiplying the internal diameter by 0.33

Question 28

When calculating the speed of sound in a closed pipe, why is the diameter multiplied by 0.3?

Answer 28

The antinode at the open end actually happens a small distance outside the pipe, this is the correction factor which is calculated by multiplying the internal diameter by 0.33

Question 28

When calculating the speed of sound in a closed pipe, why is the diameter multiplied by 0.3?

Answer 28

The antinode at the open end actually happens a small distance outside the pipe, this is the correction factor which is calculated by multiplying the internal diameter by 0.33

Question 28

When calculating the speed of sound in a closed pipe, why is the diameter multiplied by 0.3?

Answer 28

The antinode at the open end actually happens a small distance outside the pipe, this is the correction factor which is calculated by multiplying the internal diameter by 0.33

Question 28

When calculating the speed of sound in a closed pipe, why is the diameter multiplied by 0.3?

Answer 28

The antinode at the open end actually happens a small distance outside the pipe, this is the correction factor which is calculated by multiplying the internal diameter by 0.33

Question 29

When calculating the speed of sound in a closed pipe, why is the diameter multiplied by 0.3?

Answer 29

The antinode at the open end actually happens a small distance outside the pipe, this is the correction factor which is calculated by multiplying the internal diameter by 0.33