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LED and Laser diode - class-XII
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Students in a lab are trying to determine the wavelength of laser light by shining the laser through two narrow slits separated by $9.60$ micrometers toward a screen $4.00$ meters away. The first order bright fringes are $23.0$ centimeters from the center fringe.
What wavelength do the students determine?
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A
$552 nm$
💡 Explanation:
Given : $d = 9.6$ $\mu m = 9.6 \times 10^{-6}$ $m$ $D = 4.00$ $m$ $y _1 = 23$ cm $ = 0.23$ m
Distance of first order bright fringe from central fringe, $y _1 = \dfrac{\lambda D}{d}$
$\therefore$ $0.23 = \dfrac{\lambda \times 4.00}{9.6 \times 10^{-6}}$
$\implies \lambda = 0.552 \times 10^{-6}$ m $ =552$ $nm$