Sound 7&8 Flashcards
(96 cards)
1
Q
Frequency is denoted by
A
N
2
Q
SI unit of intensity of sound
A
Joule/ sec x m square. OR
Watt/ m square
3
Q
In a stethoscope sound produced by the heart is picked by a……………
A
Diaphragm
4
Q
What happens when the length of an pendulum is decreased
A
Time period decreases, frequency increases
5
Q
Wavelength is denoted by
A
λ
6
Q
Ear most sensitive to frequencies btw …………………. frequency
A
2000 to 3000 Hz
7
Q
Amplitude denoted by
A
A
8
Q
Watt=
A
Joule/ sec
9
Q
Sounds above 20 kHz
A
Ultrasonic
10
Q
Longitudinal wave also called
A
Compression waves
11
Q
Sound travels in which wave
A
Longitudinal
12
Q
No of vibrations in one second
A
Frequency
13
Q
Minimum distance needed to hear an echo
A
17 m
14
Q
Persistence of hearing
A
1/10 of a sec
15
Q
Children can hear upto ……………… Hz
A
30000
16
Q
Formula for calculating distance for an echo
A
D=vt/2
17
Q
For every 1 degree Celsius increase what is the increase in speed
A
.61m/ s
18
Q
Nodes and antinodes means
A
Nodes are situated in places of minimum displacement . While antinodes are situated at places with maximum displacement
19
Q
A dog and some fishes can hear upto
A
50 to 100 kHz,1-25Hz
20
Q
Transverse wave-
A
The particles of a medium travel perpendicular
21
Q
Sounds below 20 Hz
A
Infrasonic
22
Q
What is a longitudinal wave
A
Particles of the medium travel in the same direction
23
Q
Time taken by a particle to make one complete vibration or move a distance equal to the wavelength
A
Time period
24
Q
Range is of hearing for humans
A
20 Hz to 20000 Hz
25
................. produces sound in the human body
Larynx at the upper end of wind pipe
26
Aged people can hear upto................... kHz
10-12
27
Loud sounds more than .........harms the ear
80 db
28
Ultrasonic vs supersonic
Ultrasonic- frequency more than 20000Hz
| Supersonic- speed more than sound
29
Sound is not affected by pressure why
Because density and pressure cancel each other out
30
Ideal gas is a gas in which
Molecules do not attract or repel each other
| Molecules takes themselves no volume
31
Ideal gas law is
Pressure x volume = nRT
n - number of moles
R - universal gas constant
32
In a simple pendulum the time period of the pendulum is directly proportional to
T directly proportional to √length
33
Water speed of sound
1500 m/s
34
Granite speed of sound
6000m/s
35
Aluminium speed of sound
6420 m/s
36
Science of sound relating to the designing of buildings
Acoustics
37
Harmonics
Multiples of frequencies of sound
38
Velocity is directly proportional to
Square root of temperature
39
Quartz crystals produce ultrasonic sound when
Electricity is passed through it
40
Ultrasonic waves generated by
Small sources
41
Infrasonic waves produced by
Earthquake or seismic waves
42
Infrasonic sounds are generally generated from
Large sources
43
An important condition for the formation of echo is that
Wavelength is less than height of reflecting body
44
Music sound level
10-30 dB
45
Noise sound level
Above 120 dB
46
RADAR full form
Radio detection and ranging
47
What is a radar
Radar is an object-detection system that uses radio waves to determine the range, angle, or velocity of objects.
48
In Doppler effect when a sound emitting obj comes closer
The frequency gets higher and vice versa
49
Use of Doppler effect in radar
It helps the radar to understand if the object is coming towards or away from it
50
A radar emits
Radio waves which if there is an obj gets reflected back to the radar
51
SONAR full form
Sound navigation and ranging
52
SONAR helps in detection of
Submarines
53
Quartz produces ultrasound by the process
Piezoelectric effect
54
Loudness formula
10 x log (of) I/I°
| I° - constant I - intensity of sound
55
Power SI unit
Watt which is energy by time
56
1 watt =
I joule/ time
57
Jet at take off
140 dB
58
Pop concert
130 dB
59
Police car siren
120 dB
60
Heavy hammering machine
110 dB
61
Diesel lorry
90 dB
62
Car / motorcycle
80 dB
63
Vacuum cleaner
60 dB
64
Normal conversation
50 dB
65
Soft whisper
30
66
Recording studio
20 dB
67
Leaves rustling
10 dB
68
Dropping pin
0 dB
69
Torque :
A force that causes an object to rotate.
70
Horse power ?
Torque applied over time
71
All objects oscillate because they have a
Restoring force
72
Equilibrium position of an oscillator
Position at which 0 net force is acting on the oscillator.
| Every oscillator tries to get back to the equilibrium position but it can’t.
73
Why are some oscillators called simple harmonic motion
They have a restoring force that is directly proportional to the displacement.
74
Spring force (force provided by a spring)=
-[Spring constant (k) x displacement(x)]
= -kx
It is negative because force and displacement would act on opp directions.
It is proportional to displacement.
So an object attached to a spring shows simple harmonic motion , as the restoring force (spring force) is directly proportional to displacement.
75
The equilibrium point of a simple harmonic motion has
Maximum speed
0 restoring Force
0 acceleration
76
In simple harmonic motion , force is directly proportional to
Acceleration and not speed.
77
In a simple harmonic motion ; the end points have
Maximum restoring force , so maximum acceleration ,but still low speed (0)
78
Time by default should always be put in the ....... axis
Horizontal
79
Time period of simple Harmonic motion is not affected by
Amplitude.
If you pull the object very far from the equilibrium , then when it is restored the speed will be more. So as there is an increase in both speed and the distance it has to travel, time period remains same.
80
Time period of simple harmonic motion of an object attached to a spring depends on
Mass of the object and the spring constant. This is because the spring force (restoring force) increases on increasing the spring constant.
So if the spring constant is more then the time period will decrease.
Time period increases on increasing mass of an object.
81
Time period of simple harmonic motion of an object attached to a spring - formula
T = 2 π √(m/k)
m - mass
k - spring constant
82
Mechanical waves also called
Elastic waves
83
Loudness of sound is considered normal when it is between
50 - 60 dB
84
A dog can hear sound that has a frequency upto
50 kHz
85
Fishes can hear very low frequencies upto
1-25 Hz
86
Whales and elephants can hear infrasonic sound
T
87
Speed of sound at 0°C is
330 m/s
88
Persistence of hearing
1/10 of a second
89
Min distance for heating an echo
17 m
90
Music sound level
10 - 30 dB
91
Usually all sounds of level above ........ are considered as noise
120 dB
92
Outer ear contains
Pins and ear canal (2-3 cm)
93
Ear drum also called
Tympanum
94
Eustachian tube location
Lower part of middle layer.
| Goes to throat to maintain air pressure.
95
Cochlea contains
Nerve cells that are sensitive to sound
96
Oval window is situated
Btw middle and inner part of ear
