All Problems

Diffraction of Light

Problem 5.111

A plane monochromatic light wave falls normally on an opaque half-plane. A screen is located at a distance b=100 cmb=100 \mathrm{~cm} behind the half-plane. Making use of the Cornu spiral (Fig. 5.19 ), find: (a) the ratio of intensities of the first maximum and the neighbouring minimum; (b) the wavelength of light if the first two maxima are separated by a distance Δx=0.63 mm\Delta x=0.63 \mathrm{~mm}.

Reveal Answer
5.111. (a) Imax⁡/Imin⁡≈1.7I_{\max } / I_{\min } \approx 1.7 (b) λ=2(Δx)2/b(v2−v1)2=\quad \lambda=2(\Delta x)^{2} / b\left(v_{2}-v_{1}\right)^{2}= =0.7μm,=0.7 \mu \mathrm{m}, where v1v_{1} and v2v_{2} are the corresponding values of the parameter along Cornu's spiral.
Prev
Next