Physics 1.3 - Sound Waves

Question 1

What type of wave is sound?

Answer 1

Longitudinal

Question 2

How is sound made?

Answer 2

If nodes and antinodes are in the right spots, the object will resonate. This causes sound

Question 3

What is the equation for the speed of sound?

Answer 3

V=331+.6T

Question 4

What happens to sound with constructive and deconstructive interferance?

Answer 4

Constructive interference causes amplitude (Volume) increase. Deconstructive interference causes amplitude decrease

Question 5

What is the Doppler Effect?

Answer 5

The perceived change in pitch (frequency) of a sound detected by a listener, compared to the actual pitch produced by a moving source

Question 6

In point form, Describe the Doppler Effect

Answer 6

-When sound source is moving, the wavelength decreases
-Person will hear more waves arriving per second than there actually is. This will also cause higher frequency
-Sound source is passing by the wavelength increases
-Person will hear lower frequencies

Question 7

How much range is from quietness to loudness?

Answer 7

10^12 x the energy

Question 8

What is sound intensity measured in?

Answer 8

Decibels - dB

Question 9

What is the quietest sound that can be heard by a person? what is this called?

Answer 9

• 0dB
• Threshold of Hearing

Question 10

What is the loudest sound our ears can tolerate? what is this called?

Answer 10

• 120 dB
• Threshold of pain

Question 11

For every __a)__ increase in sound intensity, the loudness will __b)__

Answer 11

a) 10dB
b) double

Question 12

What are Beats?

Answer 12

When interference occurs in sound waves with close frequencies

Question 13

What is Resonance?

Answer 13

When a substance vibrates “as a unit” as its fundamental frequency

Question 14

How does Resonance occur?

Answer 14

Vibration of an object travels through an object and reflects back over itself from one or both ends

Question 15

Antinodes are found in __a)__ Interference and Nodes are found in __b)__ interference

Answer 15

a) constructive interference
b) Deconstructive interference

Question 16

Describe the ends of open and closed columns

Answer 16

-Closed circles an open end and a closed end
-Column is opened at both ends

Question 17

Resonance with Closed Column

Answer 17

Tuning fork is held at open end while the pipe is moved up and down until sound is produced

Question 18

When will resonance occur in a closed column

Answer 18

when there is a node at the closed end and an antinode at the open end

Question 19

What is the first resonant length

Answer 19

shortest tube which resonance can occur is at 1/4 wavelength

Question 20

What are the three resonant lengths of a closed pipe?

Answer 20

1/4, 3/4 and 5/4

Question 21

When does resonance occur in open columns?

Answer 21

when there is an antinode at both ends

Question 22

At what points will resonance occur in an open column?

Answer 22

1/2, 1 wavelength, 3/2 and 2 wavelengths