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Jainism : Through Science
P. D. = 0, 2, 2 ..... P.D.,
According to the wave theory of modern physics, when two waves from coherent sources superpose each other, the phenomenon of interference takes place. In this phenomenon if the path difference between the two waves, that are superposed on each other is 0, 2, 21, 31,....na then the crest of one wave falls on the crest of the other wave and also trough of one wave falls on the trough of the other wave and as a result constructive interference takes place. If the path difference between two waves is .....(2n-1)-then crest of one wave falls on the trough of the other wave and in same way the trough of one wave also falls on the crest of the other wave and as a result destructive interference takes place.
According to modern physics the intensity of light or waves depends upon the amplitude of waves. It is directly proportional to the amplitude. i.e. If amplitude (a) increases, intensity increases and if amplitude decreases, intensity also decreases. In the phenomenon of constructive interference, amplitude of resultant wave on account of superposition of one wave on another wave becomes double, and intensity of a wave is directly proportional to the square of its amplitude.
Ia a? (I denotes intensity, a denotes amplitude) .. I'a (2a)? (I' denotes resultant intensity)
I' a 4a2
I' = 41(:: a? = 1) According to this equation the intensity of the resultant wave in constructive interference becomes four times greater than the original single wave intensity and it is the maximum intensity of resultant wave.
While in destructive interference the resultant amplitude of the resultant wave becomes zero, hence the resultant intensity also becomes zero.
In Young's experiment, there is an illuminated slit in screen A
