10.1 sound the horns because the swine is here

Question 1

what is soudn

Answer 1

Form of energy caused by vibration

Question 2

Sound require a?

Answer 2

Medium to propogate

Question 3

Sound can propagate through ___ but cannot through ___

Answer 3

Liquid, solid, gas
Vacuum

Question 4

State how sound is transferred from a bell

Answer 4

Metal surface of bell vibrate -> air molecules near surface also vibrate & collide with air molecules nearby -> transferred in form of wave

Question 5

How is transfer of sound in solid

Answer 5

Very rapid
Particles at one end start to vibrate -> causes nearby particles to also vibrate -> solid particles arranged very closely

Question 6

How is speed of sound in liquid

Answer 6

Loose arrangement of particles -> less rapidly

Question 7

How is speed of sound in gas

Answer 7

Very slowly -> arrangement of gas particles - far apart from each other -> delay in transfer of vibration

Question 8

If sound transfers very rapidly in solids, why cant we hear in solid

Answer 8

It takes more energy to vibrate a solid than a gas

Question 9

Which types of surface can reflect and absorb sound better & worse

Answer 9

Hard and smooth - reflector
Soft and rough - absorber

Question 10

Characteristics of R & A of sound is same as?

Answer 10

Characteristics of light

Question 11

What are two main properties of sound

Answer 11

Frequency -> pitch -> hertz (Hz)
Amplitude -> strength / loudness

Question 12

What is a hertz

Answer 12

Number of oscillations per second

Question 13

state relationship between change in amplitude & effect

Answer 13

Amplitude increase -> louder sound

Question 14

state relationship between change in frequency & effect

Answer 14

Frequency increase -> higher pitch

Question 15

What is the Doppler effect

Answer 15

Apparent change in frequency caused by the relative movement of sound source, rm of observer / both

Question 16

Explain the Doppler effect of an ambulance

Answer 16

Frequency heard increases when approaches the stationery observer
Frequency heard decreases when drives away

Question 17

On a piano, a lower note means lower?

Answer 17

Frequency / pitch

Question 18

If a spoon is knocked on differently filed glass, state the pitches and why

Answer 18

Tapping spoon on glass -> vibration -> sends sound wave through water
Most water -> slower vibration -> lower sound

Question 19

If you blow on differently filed glass, state the pitches and why

Answer 19

Blow across the top of the bottle -> set the air molecules vibrating -> produce sound waves
Least filled -> lowest sound -> more air -> slower vibrationi

Question 20

What is an echo

Answer 20

Produced when sound waves are reflected from hard surface to the listener

Question 21

What are characteristics of echo

Answer 21

Sounds the same as original sound
Takes some time to reach listener’s ears

Question 22

What is condition for echo

Answer 22

At least 17 m from object
Time must be 0.1 sec (or else will merge with original)

Question 23

What is application of reflection of sound wave in human life

Answer 23

Ultrasound, sonar

Question 24

What is ultrasound & characteristics

Answer 24

Sound wave with frequency > 20000 Hz
Cannot be heard by humans - can be heard by animals (bats) -> navigation

Question 25

Which industry is sonar used by human and for what

Answer 25

Shipping - Detect underwater object
Medical & Fisheries

Question 26

What is human hearing range

Answer 26

20 - 20000 Hz

Question 27

how does range of hearing change as we age

Answer 27

Becomes narrower
Ears lose the sensitivity to sound frequencies

Question 28

What are special devices to overcome limitation of hearing

Answer 28

Stethoscope -> doctor listen to patient heartbeat
Megaphone -> amplify voice so can be heard from distance
Hearing aid -> amplify sound entering ear

Question 29

Why speed of sound effected by temperature of air

Answer 29

Propagates faster in air of higher temp -> transfer of sound energy occur faster -> higher kinetic energy of air molecules

Question 30

How does ultrasound produce image of baby in womb

Answer 30

Ultrasound wave transmitted by scanner probed - moved across belly of pregnant mother
Reflected when hits the foetus in womb
Information from reflection shown as image on monitor