6 - Interference and differaction Questions Answers
the ratio of intensities between two coherent sound sources is 4:1. the difference of loudness in decibel between maximum and minimum intensities, when they interfere in space is
(1) 10 log2
(2) 20 log3
(3) 10 log3
(4) 20 log2
I1/I2 = 4/1 so a1/a2 = 2/1 so amax/ amin = 2+1/2-1 = 3/1 so Imax/ Imin= 9/1
now loudness L = 10 log(I/I0)
so difference of loudness = L1-L2 = 10 log (9I/I) = 10 log9 = 20 log3
two coherent light sources A and B with seperation 2λ are placed the x-axis symmetrically about the origin. they emit light of wavelength λ. obtain the position of maximas on a circle of large radius R lying in the xy plane and with the center at origin
for maxima path diffrence should be integral multiple of λ.
It is given that two coherent light sources A and B with seperation 2λ are placed on the x-axis symmetrically about the origin, and we have to get the points of maxima in the circle so at the point where circle cuts the X axis (path diffrence = 2λ) and where circle cuts the Y axis (path difference = 0) will be the point of maxima. Besides it one point will also be present in the circle in first quadrant where path difference will be λ so it will be a maxima also. it means total 8 points are there
two sound waves having intensities 4 unit and 9 unit coming from two coherent sources arrive at a point along the same line simultaneously in same phase. resultant intensity at the point will be
Use the formule I = I1 + I2 + 2 √I1 √I2 cosθ
here θ = 0
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two sound sources of intensity I and 4I are used in an interference experiment. find the intensity at points where the waves from the two sources are superimposed with a phase difference of
(1) zero
(2) π/2
93)π
Use the formule I = I1 + I2 + 2 √I1 √I2 cosθ
here θ = 0
two waves are represented by y = Acosωt and y = Asin(ωt - π/6), superimpose on each other. the amplitude of the rsultant wave is
first convert cos into sin then calculate phase difference, its value will be π/2 + π/6 = 2π/3
now use the formula for resultant amplitude
which of the following phenomenon cannot be observed with sound waves?
(1) diffraction
(2) polarisation
(3) reflection
(4) interference
polarisation