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Wave Optics

JEE Main level, single correct, medium

124 of 191

Question 124 of 191

A slit of width $a$ is illuminated by light of wavelength $\lambda$ . The linear separation between $1^{st}$ and $3^{rd}$ minima in the diffraction pattern produced on a screen placed at a distance $D$ from the slit system is _____.

Show answer and solution

Answer: (C) $2\dfrac{D\lambda}{a}$

The position of the

n^{th}

minimum in a single slit diffraction pattern on a screen at distance

D

is given by

y_n = \dfrac{n D \lambda}{a}

.

For the

1^{st}

minimum,

n = 1

, so

y_1 = \dfrac{D \lambda}{a}

.

For the

3^{rd}

minimum,

n = 3

, so

y_3 = \dfrac{3 D \lambda}{a}

.

The linear separation between the

1^{st}

and

3^{rd}

minima on the same side of the central maximum is

\Delta y = y_3 - y_1

\Delta y = \dfrac{3 D \lambda}{a} - \dfrac{D \lambda}{a} = 2\dfrac{D \lambda}{a}

.

Answer:

2\dfrac{D\lambda}{a}

JEE Main question paper PDF

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JEE Main 2025 Apr 2 Shift 1 question paper

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More Physics practice

JEE Main Physics practice question on Wave Optics (Diffraction of Light), with the answer and a step-by-step solution. Scan a question from your own book or paper to get a whiteboard video.

A slit of width aaa is illuminated by light of wavelength λ\lambdaλ. The linear separation between 1st1^{st}1st and 3rd3^{rd}3rd minima in the diffraction pattern produced on a screen placed at a distance DDD from the slit system is _____.

JEE Main question paper PDF

More Physics practice

A slit of width $a$ is illuminated by light of wavelength $\lambda$ . The linear separation between $1^{st}$ and $3^{rd}$ minima in the diffraction pattern produced on a screen placed at a distance $D$ from the slit system is _____.