NEET-XII-Physics
17: Light Waves
- #8In a Young’s double slit experiment, two narrow vertical slits placed 0⋅800 mm apart are illuminated by the same source of yellow light of wavelength 589 nm. How far are the adjacent bright bands in the interference pattern observed on a screen 2⋅00 m away?Ans : Given:
Separation between two narrow slits, `` d=0.8\,\mathrm{\,mm\,}=0.8\times {10}^{-3}\,\mathrm{\,m\,}``
Wavelength of the yellow light, `` \lambda =589\,\mathrm{\,nm\,}=589\times {10}^{-9}\,\mathrm{\,m\,}``
`` ``
Distance between screen and slit, `` D=2.0\,\mathrm{\,m\,}``
Separation between the adjacent bright bands = width of one dark fringe
That is, `` \beta =\frac{\lambda D}{d}`` ...(i)
`` \Rightarrow \beta =\frac{589\times {10}^{-9}\times 2}{0.8\times {10}^{-3}}``
`` =1.47\times {10}^{-3}\,\mathrm{\,m\,}``
`` =1.47\,\mathrm{\,mm\,}.``
Hence, the adjacent bright bands in the interference pattern are 1.47 mm apart.
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