Wave Optics | Physics JEE previous year questions with Solutions

Q 1 :
A monochromatic light of wavelength 6000 $Å$ is incident on the single slit of width 0.01 mm. If the diffraction pattern is formed at the focus of the convex lens of focal length 20 cm, the linear width of the central maximum is [2024]

60 mm
24 mm
120 mm
12 mm

1

2

3

4

(B) $Angular width = \frac{2 λ}{a}$

$Linear width = \frac{2 λ}{a} \cdot f$

$= \frac{2 \times 6000 \times 10^{- 10} \times 20 \times 10^{- 2}}{0.01 \times 10^{- 3}}$

$= 24 \times 10^{- 3} m = 24 mm$

Q 2 :
A microwave of wavelength 2.0 cm falls normally on a slit of width 4.0 cm. The angular spread of the central maxima of the diffraction pattern obtained on a screen 1.5 m away from the slit will be [2024]

30°
15°
60°
45°

1

2

3

4

(C) $d \sin θ = λ (Half angular speed)$

$\sin θ = \frac{λ}{d} = \frac{2 \times 10^{- 2}}{4 \times 10^{- 2}} = \frac{1}{2} \Rightarrow θ = 30 °$

$Full angular speed = 2 θ = 60 °$

Q 3 :
A parallel beam of monochromatic light of wavelength 600 nm passes through a single slit of 0.4 mm width. Angular divergence corresponding to the second order minima would be ____ × $10^{- 3}$ rad. [2024]

0%

(6) $\sin θ ≃ θ ≃ \frac{2 λ}{b}$

$= \frac{2 \times 600 \times 10^{- 9}}{4 \times 10^{- 4}} = 3 \times 10^{- 3} rad$

Total divergence = $(3 + 3) \times 10^{- 3} = 6 \times 10^{- 3} r a d$

Q 4 :
A parallel beam of monochromatic light of wavelength 5000 $Å$ is incident normally on a single narrow slit of width 0.001 mm. The light is focused by a convex lens on the screen, placed on its focal plane. The first minima will be formed for the angle of diffraction of ____ (degree). [2024]

0%

(30) For first minima

$a \sin θ = λ$

$\Rightarrow \sin θ = \frac{λ}{a} = \frac{5000 \times 10^{- 10}}{1 \times 10^{- 6}} = \frac{1}{2}$

$\Rightarrow θ = 30 °$

Topic Question Set

Q 1 :
A monochromatic light of wavelength 6000 $Å$ is incident on the single slit of width 0.01 mm. If the diffraction pattern is formed at the focus of the convex lens of focal length 20 cm, the linear width of the central maximum is [2024]

Q 2 :
A microwave of wavelength 2.0 cm falls normally on a slit of width 4.0 cm. The angular spread of the central maxima of the diffraction pattern obtained on a screen 1.5 m away from the slit will be [2024]

Q 3 :
A parallel beam of monochromatic light of wavelength 600 nm passes through a single slit of 0.4 mm width. Angular divergence corresponding to the second order minima would be ____ × $10^{- 3}$ rad. [2024]

0%

Q 4 :
A parallel beam of monochromatic light of wavelength 5000 $Å$ is incident normally on a single narrow slit of width 0.001 mm. The light is focused by a convex lens on the screen, placed on its focal plane. The first minima will be formed for the angle of diffraction of ____ (degree). [2024]

0%

Want Us to Email you About Special Offers & Updates?

Topic Question Set

Q 1 : A monochromatic light of wavelength 6000 Å is incident on the single slit of width 0.01 mm. If the diffraction pattern is formed at the focus of the convex lens of focal length 20 cm, the linear width of the central maximum is [2024]

Q 2 : A microwave of wavelength 2.0 cm falls normally on a slit of width 4.0 cm. The angular spread of the central maxima of the diffraction pattern obtained on a screen 1.5 m away from the slit will be [2024]

Q 3 : A parallel beam of monochromatic light of wavelength 600 nm passes through a single slit of 0.4 mm width. Angular divergence corresponding to the second order minima would be ____ × 10-3 rad. [2024]

0%

Q 4 : A parallel beam of monochromatic light of wavelength 5000Å is incident normally on a single narrow slit of width 0.001 mm. The light is focused by a convex lens on the screen, placed on its focal plane. The first minima will be formed for the angle of diffraction of ____ (degree). [2024]

0%

Want Us to Email you About Special Offers & Updates?

Q 1 :
A monochromatic light of wavelength 6000 $Å$ is incident on the single slit of width 0.01 mm. If the diffraction pattern is formed at the focus of the convex lens of focal length 20 cm, the linear width of the central maximum is [2024]

Q 2 :
A microwave of wavelength 2.0 cm falls normally on a slit of width 4.0 cm. The angular spread of the central maxima of the diffraction pattern obtained on a screen 1.5 m away from the slit will be [2024]

Q 3 :
A parallel beam of monochromatic light of wavelength 600 nm passes through a single slit of 0.4 mm width. Angular divergence corresponding to the second order minima would be ____ × $10^{- 3}$ rad. [2024]

Q 4 :
A parallel beam of monochromatic light of wavelength 5000 $Å$ is incident normally on a single narrow slit of width 0.001 mm. The light is focused by a convex lens on the screen, placed on its focal plane. The first minima will be formed for the angle of diffraction of ____ (degree). [2024]