Angular width of the central maxima in the Fraunhofer diffraction for =6000Å is _0. When the same slit is illuminated by another monochromatic light, the angular width decreases by 30 \%. The wavelen…

Question

Angular width of the central maxima in the Fraunhofer diffraction for =6000Å is _0. When the same slit is illuminated by another monochromatic light, the angular width decreases by 30 \%. The wavelength of this light is [NEET 2019]

Accepted Answer

Correct answer: B. (b) The angular width of central maxima is given by 2 = 2 a …….(i) where, = wavelength of light used a= width of the slit For _1=6000Å ,2 = _0 (given) For another light of wavelength _2 (says), the angular width decreases by 30 \%, so 2 = ( 100-30100 ) _0= 70100 _0=0.7 _0 As slit width is constant, so using Eq. (i) for these values, we get _00.7 _0= _1 _2 ⇒ _2= _1 0.7 =6000 0.7=4200Å

$Angular width of the central maxima in the Fraunhofer diffraction for is . When the same slit is illuminated by another monochromatic light, the angular width decreases by . The wavelength of this light is [NEET 2019]$

Solution

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