1. Tardigrade
  2. Question
  3. Physics
  4. Light of wavelength λ=5000 mathringA falls normally on a narrow slit. A screen is placed at a distance of 1 m from the slit and perpendicular to the direction of light. The first minima of the diffraction pattern is situated at 5 mm from the centre of central maximum. The width of the slit is

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Q. Light of wavelength $\lambda=5000\,\mathring{A}$ falls normally on a narrow slit. A screen is placed at a distance of $1 \,m$ from the slit and perpendicular to the direction of light. The first minima of the diffraction pattern is situated at $5\, mm$ from the centre of central maximum. The width of the slit is

Wave Optics

Solution:

Position of $n$ th minima $x_{n}=\frac{n \lambda D}{d}$
$\Rightarrow 5 \times 10^{-3}=\frac{1 \times 5000 \times 10^{-10} \times 1}{d}$
$\Rightarrow d=10^{-4} m =0.1 \,mm$.