12) Prove that at a distance r straight infront of a point source with power P, moving with constant speed vs, the wave intensity is\frac{P}{4\Pi r^{2}}(\frac{v - v_{s}}{v}).
1) The atomic mass of iodine is 127g/mol. A standing wave in iodine vapour at 400K has nodes that are 6.77 cm apart when the frequency is 1000Hz. At this temperature, is iodine vapour mono-atomic or diatomic?
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113) When beats are produced by two progressive wave trains of same amplitude and of nearly same frequencies, then the maximum loudness at the waxing heard is n times the loudness of each the component wave trains. the value of n is ___.
14) A source of sound with frequency f0 = 1.8 kHz moves uniforml along a straight line separated from a stationary observer by a distance l = 250 m. The velocity of the source is equal to n = 0.8 fraction of the velocity of sound. Find :
(a) the frequency of sound received by the observer at the moment when the source gets closest to him;
(b) the distance between the source and observer at the moment when the observer receives a frequecy f = f0.
(can (b) actually happen???)
15) Does a phase difference of a multiple of 2Î ( 2Î , 4Î , 6Î ,... ) have any sense or does it merely indicate a ZERO phase difference???
1it's been three days since these questions are lying unanswered!!!! i desperately need help!!!
115) Does a phase difference of a multiple of 2Î ( 2Î , 4Î , 6Î ,... ) have any sense or does it merely indicate a ZERO phase difference???
Because a sinusoidal wave repeats its shape after every 2Î rad, a phase difference φ = 2Î
corresponds to a shift of one wave relative to the other wave by a distance equivalent to one
wavelength.
11Euclid answer sahi hai kya?
because am not very sure about it. saw this in one book.
tell if its correct
23for 1st ,
v = √γRTM = 10 x 2 x 6.77
so γM = 5.512
for monoatomic , M = 127 x 10-3kg/mole , γ = 5/3 , so γM ≈ 13.12
for diatomic , M = 254 x 10-3 kg / mole , γ = 7/5
γM = 5.51
hence diatomic
23for 3rd mostly the question is based on loudness in terms of decibels
i also didnt understand Q4
for Q 2, let Eavg= avg energy stored in one wavelength,
now one wavelength will pass thru a pt in time T , so in one sec 1/T wavelengths pass thru a pt
so in one sec Eavg/T energy is transmitted thru a pt wich is the avg power
hence power = Eavg/T =Evg f
so intensity = Eavgf 4Ï€r2
now if fo = freq of waves when source isnt moving ,
then P = Evg fo
so power when source is moving is Pffo
hence intensity = Pf 4Ï€r2fo