|
(ii) Applciation : To determine the velocity of sound the frequency of tuning fork.
(iii) Formula :If the first & second resonance length are L1 and l2 then
(19).(a) Velocity of sound (Longitudinal wave) in elastie medium:
E= coefficint of elasticity of medium, d =density for a soled medium:
E= y = young coefficient of elastucity.
In a liquid medium:
E= y = youngs cofficient of elasticity .
In aliquuid medium:
E = k= cofficent of volume elasticity.
In gossous medium:
M= moleculer, p=pressure, T= temperature.
(b). In stretched vibrating wire or a string , the velocity of a transverse ware:
(20) Factore affecting the velocity of sound in gas:
Factor |
Effect |
(i) Pressure |
No effect |
(ii) density |
 velocity decreases with the increases in density. |
(iii) tempreture |
 with temprature rin the velocity increases |
(iv) humidity |
Velocity in humid air is more then in dry air
 hear P = atmospheric pressure, f = water vapour pressure |
(iv) At 00C velocity of sound in dry air = 332 m/sec. while the velocity sound in water is 1440 m/sec. At t0 C the velocity of soundwill be (for low value of t, t/273 << 1 )
Vt = 330 + 0.61 [m/sec.]
(vi) If atomic weights of two gases are M1 and M2 recpectively them
21.
Feature of musical sound:
(i) Loudness: The quality of sound on the leasis of which , sound is said to br high on low . It depends on the .
(i) shape of the soure,
(2) intensity of sound ,
unit of L is "phone"where
I is measured in decible.
The amplitude of a roaring Lion is more than sound produced by a mosquito.
(ii) Pitch : On the basis of this characteristie said to be shary or dull. Pitch inereases with the frequency of sound.
For example pitch of roaring Lin is less than that of sound of a mosquito.
(ii). Quality : On the basis of this property the sounds of same loudness and pitch can bedifferentiated. The basis of this differentiaten is number of harmonics present in the sound, relatine intensity etc. On enireasing the number of overtones, sweetness of the sound encreases. Example: Whisttis sound (closed pipe) /> is less sweet then that of flute (open pipe).
22.
some Important informations
:
(i)shock waves: s body moving with a supersonic velocity leaves behijnd itself a conical distubance region. Disturbance of this kind is larhe amount of erergy which can danage the buildings.
(ii)Frequency of infrosonic waves is less than 20 Hz.
(iii)Mach number =
(v)Vibration of tuning fork : When tuning fork is sounded by striking its one and on rubber pad, then:
(a) the ands of prongs vibrate in and out while the stem virates up and sown or vibrations of the prongs are transverse and that of the stem is longitudinal . Generally tuning fork produces fundamental note.
(b) St the free and of a fork antinodes are farmed. St the place where stem is fixed antinode is farmed.
(c)Frequency of tunig fork
t = thickness of turing fork.
L =length of arm of fork.
E = cocffuient of clssticity for the material of fork.
d = denrity of the material of a fork.
e Frequency of tuning fork decrease with increase in temperature.
(e)eneriasing the weight, the frequency of a tuning fork dureases while on filing the prongs near stem the frequency decreases.
|
E-Store
