SATHEE: wave-optics Question 30

wave-optics Question 30

Question: Q. 9. (i) In Young’s double slit experiment, describe briefly how bright and dark fringes are obtained on the screen kept in front of a double slit. Hence obtain the expression for the fringe width.

(ii) The ratio of the intensities at minima to the maxima in the Young’s double slit experiment is $9 : 25$ . Find the ratio of the width of the slits.

U [O.D. I, II, III 2014]

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Solution:

Ans. (i) Try yourself similar to Q. 2 (i) LAT Questions. 311/2 Now, fringe width,

$β =$ separation between two successive maxima (or two successive minima)

$\begin{aligned} = x_{n} - x_{n - 1} ∴ β & = \frac{λ D}{d} \end{aligned}$

(ii) We have

$\frac{I_{max}}{I_{min}} = \frac{{(a_{1} + a_{2})}^{2}}{{(a_{1} - a_{2})}^{2}} = \frac{25}{9}$

$\begin{array}{ll} ∴ & \frac{a_{1} + a_{2}}{a_{1} - a_{2}} = \frac{5}{3} \Rightarrow \frac{a_{1}}{a_{2}} = \frac{4}{1} ∴ & \frac{w_{1}}{w_{2}} = \frac{I_{1}}{I_{2}} = \frac{{(a_{1})}^{2}}{{(a_{2})}^{2}} = \frac{16}{1} \end{array}$

[CBSE Marking Scheme 2014]

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wave-optics Question 30

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Wave Optics

wave-optics Question 30

Table of Contents

Engineering Preparation

Medical Preparation

NCERT Books & Solutions

Important Resources

Other Resources

Syllabus

Test Platform

Sample Mock Test

Mentorship

NCERT Exercise Video Solution

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