A light wave is incident normally over a slit of width 24 10^ -5 … - Vidyadip

MCQ

A light wave is incident normally over a slit of width $24 \times 10^{-5}\, cm.$ The angular position of second dark fringe from the central maximum is $30^o .$ What is the wavelength of light .......$\mathop A\limits^o $

✓
$6000$
B
$5000$
C
$3000$
D
$1500$

✓

Answer

Correct option: A.

$6000$

a
For $2^{\text {nd }}$ dark

$\mathrm{d} \sin \theta=2 \lambda$

$\lambda = \frac{{{\rm{d}}\sin \theta }}{2} = \frac{{24 \times {{10}^{ - 5}}\sin {{30}^\circ }}}{2} = 6 \times {10^{ - 5}}{\rm{\,cm}} = 6000\mathop {\rm{A}}\limits^o $

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