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Two coherent fight sources A and B with separation 2lambda are placed on the x-axis symme-trically about the origion. They emit light of wavelength lambda. Obtain the positions of maxima on a circle of large radius, lying in the x-y plane and with centre at the origion. |
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Answer» SOLUTION :For P to have maximum INTENSITY, `d cos theta= n lambda` `2lambda cos theta = n lambda ""cos theta = (n)/(2)` where n is integer For `n=0, theta = 90^(@), 270^(@)` `n= pm1, theta= 60^(@), 120^(@), 240^(@), 300^(@)` `n= pm2, theta = 0^(@), 180^(@)` So, position of maxima are at `theta= 0^(@), 60^(@), 120^(@), 180^(@), 240^(@), 270^(@)" and "300^(@)` i.e., 8 positions will be obtained. Short cut : In `d= n lambda` then number ofmaximum on the circle is 4n. |
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