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TS EAMCET · Physics · Wave Optics

A light beam of wavelength \(800 \mathrm{~nm}\) passes through a single slit and projected on a screen lsept at \(5 \mathrm{~m}\) away from the slit. What should be the slit width for the ray optics approximation to be valid?

  1. A \(0.5 \mathrm{~mm}\)
  2. B \(2 \mathrm{~mm}\)
  3. C \(1.5 \mathrm{~mm}\)
  4. D \(0.25 \mathrm{~mm}\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(2 \mathrm{~mm}\)

Step-by-step Solution

Detailed explanation

Ray optics approximation can be taken upto FresneIs' distance which is given by \[ z_f=\frac{a^2}{\lambda} \] Given, \(\quad Z_f=5 \mathrm{~m}\), wavelength, \(\lambda=800 \mathrm{~nm}=800 \times 10^{-9} \mathrm{~m}\), Slit width \(a=\) ?…