InterviewSolution
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InterviewSolution
| 1. |
For a single slit of width a, the first minimum of diffraction pattern of amonochromatic light of wavelength lambda occurs at an angle of lambda//a. At the same angle of lambda//a, we get a maximum for two narrow slits separated by a distance a. Explain. |
| Answer» Solution :In the interference pattern due to narrow slits separated by distance `a`, path differecne`= a sin theta`. For constructive interference, `a sin theta = 1 lambda, sin theta ~= theta = lambda//a`, we get a MAXIMUM. In the diffraction pattern due to a SINGLE SLIT, when path differencefrom secondary waves from the ends of wavefront is `lambda`, then for every pointin one half of the LOWER half for which path diff. between secondary waves is `lambda//2`. Therefore, interference is destructive and we obtain first minimum at the same angle. | |