Sound

Question 1

What are the two things that must be present in the production of sound?

Answer 1

Something that vibrates

Something that Resonates

Question 2

Number of waves per second

Answer 2

Frequency (measured in Hz)

Question 3

Frequency is perceived subjectively as what?

Answer 3

Pitch

Question 4

The lower the pitch, the lower the ______________?

Answer 4

Frequency

Question 5

A lower pitch has a ________(longer, shorter) wave.

Answer 5

Longer

Question 6

Speed of Sound in AIR

Answer 6

340 m/sec

Question 7

What is the human range for frequency?

Answer 7

20-20,000 Hz

Question 8

Below 20 Hz

Answer 8

infrasonic

Question 9

Above 20,000 Hz

Answer 9

ultrasonic

Question 10

Measurement unit for loudness

Answer 10

Decibels (dB)

Question 11

Practical range for loudness (humans)

Answer 11

0 dB to 120 dB

Question 12

If the decibel level is 10 times greater, the sound is _____ as loud.

Answer 12

Twice.

Question 13

What type of wave is sound?

Answer 13

Longitudinal

Question 14

Why is it silent in outer space?

Answer 14

There is not medium (no air) for sound to travel in.

Question 15

A vibrating object forces a second object to vibrate

Answer 15

Forced vibration

Question 16

An object with elasticity will vibrate at its own frequency. This is the object’s ___________________.

Answer 16

Natural Frequency

Question 17

This happens when forced vibrations take place at the natural frequency, creating a peak of energy

Answer 17

Resonance

Question 18

What happens when two identical waves come together and are out of phase?

Answer 18

The sound becomes muted or muffled.

Question 19

What happens when two identical waves come together and are in phase?

Answer 19

The amplitude of the wave is increased and the sound becomes louder.

Question 20

The difference in two sounded frequencies is called what?

Answer 20

The Beat Frequency

Question 21

If two tones of slightly different frequencies are sounded together, what happens to the sound?

Answer 21

There is a periodic variation in the loudness of the sound.

Question 22

A periodic variation in the loudness of sound

Answer 22

Beats

Question 23

Doppler Effect

Answer 23

An apparent shift in frequency due to the motion of a source, an observer or both

Question 24

With the Doppler Effect, the wavelength is _____________ as a source approaches, making the frequency __________________.

Answer 24

Shortened; Higher

Question 25

With the /Doppler Effect, the wavelength is ______________ as a source leaves, making the frequency ___________.

Answer 25

Lengthened; Lower

Question 26

Doppler Effect can occur with ___________ or _____________.

Answer 26

Sound; Light

Question 27

If objects move away from an observer, there is a ______________ frequency or a _____ shift.

Answer 27

Lower; Red

Question 28

If objects move towards the observer, there is a _______________ frequency or a ________ shift.

Answer 28

Higher; Blue