All Problems

Diffraction of Light

Problem 5.113

A plane monochromatic light wave falls normally on a long rectangular slit behind which a screen is positioned at a distance b=60 cm.b=60 \mathrm{~cm} . First the width of the slit was adjusted so that in the middle of the diffraction pattern the lowest minimum was observed. After widening the slit by Δh=0.70 mm,\Delta h=0.70 \mathrm{~mm}, the next minimum was obtained in the centre of the pattern. Find the wavelength of light.

Reveal Answer
 5.113. λ=(Δh)2/2b(v2−v1)2=0.55μm, where v1 and v2 are  the corresponding values of the parameter along Cornu’s spiral. \begin{aligned} &\text { 5.113. } \lambda=(\Delta h)^{2} / 2 b\left(v_{2}-v_{1}\right)^{2}=0.55 \mu \mathrm{m}, \text { where } v_{1} \text { and } v_{2} \text { are }\\ &\text { the corresponding values of the parameter along Cornu's spiral. } \end{aligned}
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