A slit of width is illuminated by light of wavelength . The linear separation between and minima in the diffraction pattern

Question

A slit of width $a$ is illuminated by light of wavelength $λ$ . 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 ______. [2026]

Smart Achievers · Accepted Answer

(3)

$For minima, y = \frac{n D λ}{a}$

$D$

$3rd minima, y = \frac{3 D λ}{a}$

$Separation Δ y = y_{3} - y_{1} = \frac{2 D λ}{a}$

Solution

Q.
A slit of width $a$ is illuminated by light of wavelength $λ$ . 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 ______. [2026]

1 $\frac{D λ}{a}$

2 $1.5 \frac{D λ}{a}$

3 $2 \frac{D λ}{a}$

4 $3 \frac{D λ}{a}$

Ans.
(3)

$For minima, y = \frac{n D λ}{a}$

$1st minima y = \frac{D λ}{a}$

$3rd minima, y = \frac{3 D λ}{a}$

$Separation Δ y = y_{3} - y_{1} = \frac{2 D λ}{a}$

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Solution

Q. A slit of width a is illuminated by light of wavelength λ. The linear separation between 1st and 3rd minima in the diffraction pattern produced on a screen placed at a distance D from the slit system is ______. [2026]

1 Dλa

2 1.5Dλa

3 2Dλa

4 3Dλa

Ans. (3) For minima, y=nDλa 1st minima y=Dλa 3rd minima, y=3Dλa Separation Δy=y3-y1=2Dλa