Ch 2 (Sound)

Question 1

Sound

Answer 1

All sounds are produced by the viberation of objects. Sound is a form of energy that travels in the form of waves from one place to another.

Question 2

Condition for production of sound

Answer 2

The body should viberate

Question 3

Loudness

Answer 3

Characteristic of sound by which loud and faint sounds can be distinguished

Question 4

Loudness c

Answer 4

Characteristic of sound by which loud and faint sounds can be distinguished
Eg,
Adressing to friend and adressing to a gathering

Question 5

Factors affecting loudness

Answer 5

4
Amplitude of viberating body
Area of viberating body
Distance from viberating body
Hearing ability of listener

Question 6

Relation of loudness with amplitude

Answer 6

Directly proportional

Question 7

Relation of loudness with area

Answer 7

Directly proportional

Question 8

Relation of loudness with distance

Answer 8

Inversely propotional
Due to a decrease in amplitude due to an increase in distance

Question 9

Pitch

Answer 9

The characteristic of sound by which we can distinguish between shrill and grave sound

Question 10

Pitch depends on? How?

Answer 10

Frequency
Directly proportional

Question 11

Quality

Answer 11

Characteristic of sound by which we can distinguish two sounds of same pitch and loudness
For example. Notes of piano and a flute

Question 12

Quality depends on

Answer 12

Waveform

Question 13

Intensity

Answer 13

Sound energy passing through a unit area held perpendicular to the direction of propogation of sound waves

Question 14

Unit of intensity

Answer 14

W per m²
Watt per meter square

Question 15

Dogs can hear frequency?

Answer 15

20,000 to 25,000 Hz

Question 16

Zero bel

Answer 16

The barely audible and faintest intensity of sound is (10 raised to power minus 12)

Question 17

Intensity level

Answer 17

The difference between loudness of unknown sound and loudness L⁰ is called intensity level

Question 18

Decibel scale

Answer 18

A scale used for measuring intensity of sound. It is the lagorithmic measure of amplitude of sound waves. In the logarithmic scale, equal intervals correspond to multiplying by 10 instead of adding equal amounts.

Question 19

Formula for intensity level

Answer 19

10 log I/I⁰ dB

Question 20

Intensity in Wm² and dB of jet plane

Answer 20

10 ³ and 150

Question 21

Intensity in Wm² and dB of siren

Answer 21

10⁰ and 120

Question 22

Intensity in Wm² and dB of whisper

Answer 22

10-⁹ and 30

Question 23

Intensity in Wm² and dB rustling if leaves

Answer 23

10-¹¹ and 10

Question 24

Intensity in Wm² and dB of threshold

Answer 24

10-¹² and 0

Question 25

Reflection of sound (echo)

Answer 25

Sound travelling in a medium falls on another medium bouces back to the first medium

Question 26

Blue whale’s rumble (dB)

Answer 26

180 dB

Question 27

Musical sounds

Answer 27

Sounds pleasant for our ears, eg flute violen etc

Question 28

Noise

Answer 28

Sounds that produce unpleasant and jarring effects on our ears, eg, slamming of door and sounds of traffic etc

Question 29

Noise pollution

Answer 29

Level of noise that has bad effect on human health, animals and plants etc eg sound of traffic, heavy machinery

Question 30

Safe level of noise for humans

Answer 30

85 to 90 dB

Question 31

Health effects of noise pollution

Answer 31

Aggression,high stress level , hearing loss, sleep disturbances etc

Question 32

Acoustics

Answer 32

Study of sounds, its effects, properties and production

Question 33

Acoustic protection

Answer 33

The technique or method used to absorb undesireable sounds by soft and porous surfaces

Question 34

Reverberations

Answer 34

Sometimes, when the sound is reflected by the walls, ceilings, and floor, the reflecting surfaces are too reflecting, and sound becomes garbled. This is due to multiple reflections called reverberations.

Question 35

Audible frequency for humans

Answer 35

20 to 20,000 Hz

Question 36

Audible Frequency range def

Answer 36

The range of frequencies that humans can hear

Question 37

Ultrasounds def

Answer 37

Sounds of frequency higher than 20,000 Hz which are inaudible to human ear are called ultrasounds or ultrasonic waves

Question 38

Bats’ audible frequency

Answer 38

Up to 120,000

Question 39

Mice audible frequency

Answer 39

Up to 100,000