Sign in
12thPass logo
New chatPYQ LibraryDoubtsRank report
Sign in to see Recents

Your guest activity stays on this device

Sign in to save progress →
Sign in

Wave Optics question

2021 · 26 Feb · Shift 1 · Q50
Guest · filters and generic practice availableBrowsing as a guest · PYQ filters and generic practice are available. Sign in only for personalised features and saved progress.
  1. PYQ Library
  2. /JEE Main
  3. /Physics
  4. /Wave Optics
  5. /2021 · 26 Feb · Shift 1 · Q50

Wave Optics question

2021 · 26 Feb · Shift 1 · Q50

JEE MainPhysicsWave OpticsMCQ+4 / −1
In a Young's double slit experiment two slits are separated by 2 mm and the screen is placed one meter away. When a light of wavelength 500 nm is used, the fringe separation will be :
  1. A
    0.50 mm
  2. B
    0.25 mm
  3. C
    1 mm
  4. D
    0.75 mm
View written solutionFree

Correct answer: B

  1. Use the formula for fringe width in Young’s double slit experiment

    The fringe separation (fringe width) is β=λDd\beta = \frac{\lambda D}{d}β=dλD​ where:

    • λ=500 nm=500×10−9 m\lambda = 500\,\text{nm} = 500 \times 10^{-9}\,\text{m}λ=500nm=500×10−9m
    • D=1 mD = 1\,\text{m}D=1m
    • d=2 mm=2×10−3 md = 2\,\text{mm} = 2 \times 10^{-3}\,\text{m}d=2mm=2×10−3m

  2. Substitute the values

    β=(500×10−9)(1)2×10−3\beta = \frac{(500 \times 10^{-9})(1)}{2 \times 10^{-3}}β=2×10−3(500×10−9)(1)​

  3. Simplify

    β=5002×10−9+3\beta = \frac{500}{2} \times 10^{-9+3}β=2500​×10−9+3 β=250×10−6 m\beta = 250 \times 10^{-6}\,\text{m}β=250×10−6m β=2.5×10−4 m\beta = 2.5 \times 10^{-4}\,\text{m}β=2.5×10−4m

  4. Convert into mm

    Since 1 mm=10−3 m1\,\text{mm} = 10^{-3}\,\text{m}1mm=10−3m, β=2.5×10−4 m=0.25 mm\beta = 2.5 \times 10^{-4}\,\text{m} = 0.25\,\text{mm}β=2.5×10−4m=0.25mm

  5. Match with the options

    0.25 mm0.25\,\text{mm}0.25mm corresponds to Option B.

Final Answer: B. 0.25 mm0.25\,\text{mm}0.25mm

PreviousNext

More from Wave Optics

  • The light waves from two coherent sources have same intensity I1 = I2 = I0. In interference pattern the intensity of light at minima is zero. What will be the intensity of light at maxima?2021 · MCQ
  • In Young's double slit experiment, if the source of light changes from orange to blue then :2021 · MCQ
  • The difference in the number of waves when yellow light propagates through air and vacuum columns of the same thickness is one. The thickness of the air column is ​ mm. [Refractive index of air = 1.0003, wavelength…2021 · Numerical
  • In a Young's double slit experiment, the slits are separated by 0.3 mm and the screen is 1.5 m away from the plane of slits. Distance between fourth bright fringes on both sides of central bright is 2.4 cm. The frequency of light used is ​×…2021 · Numerical
  • Interference fringes are observed on a screen by illuminating two thin slits 1 mm apart with a light source (λ = 632.8 nm). The distance between the screen and the slits is 100 cm. If a bright fringe is observed on a screen at a…2020 · MCQ
  • In a Young’s double slit experiment, 16 fringes are observed in a certain segment of the screen when light of a wavelength 700 nm is used. If the wavelength of light is changed to 400 nm, the number of fringes observed in the same segment…2020 · MCQ
  • In a Young’s double slit experiment, light of 500 nm is used to produce an interference pattern. When the distance between the slits is 0.05 mm, the angular width (in degree) of the fringes formed on the distance screen is close to2020 · MCQ
  • Two light waves having the same wavelength λ in vacuum are in phase initially. Then the first wave travels a path L1 through a medium of refractive index n1 while the second wave travels a path of length L2 through a medium of…2020 · MCQ