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

2018 · Q130
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. /NEET
  3. /Physics
  4. /Wave Optics
  5. /2018 · Q130

Wave Optics question

2018 · Q130

NEETPhysicsWave OpticsMCQ+4 / −1
In Young’s double slit experiment the separation d between the slits is 2 mm, the wavelength λ\lambdaλ of the light used is 5896 A0\mathop A\limits^0A0​ and distance D between the screen and slits is 100 cm. It is found that the angular width of the fringes is 0.20o. To increase the fringe angular width to 0.21o (with same λ\lambdaλ and D) the separation between the slits needs to be changed to
  1. A
    1.9 mm
  2. B
    1.8 mm
  3. C
    2.1 mm
  4. D
    1.7 mm
View written solutionFree

Correct answer: A

Angular width = λd{\lambda \over d}dλ​

∴\therefore∴ 0.20o = λ2{\lambda \over 2}2λ​

⇒\Rightarrow⇒ λ\lambda λ = 0.2 ×\times× 2

Again, 0.21o = λd{\lambda \over d}dλ​

So using value of λ, we have

d = 0.20×20.21{{0.20 \times 2} \over {0.21}}0.210.20×2​ = 1.9 mm

PreviousNext

More from Wave Optics

  • Unpolarised light is incident from air on a plane surface of a material of refractive index μ. At a particular angle of incidence i, it is found that the reflected and refracted rays are perpendicular to each other. Which of the…2018 · MCQ
  • Young's double slit experiment is first performed in air and then in a medium other than air. It is found that 8th bright fringe in the medium lies where 5th dark fringe lies in air. The refractive index of the medium is nearly2017 · MCQ
  • The ratio of resolving powers of an optical microscope for two wavelength λ1 = 4000 A∘​ and λ2​ = 6000 A∘​ is2017 · MCQ
  • Two polaroids P1 and P2 are placed with their axis perpendicular to each other. Unpolarised light I0 is incident on P1. A third polaroid P3 is kept in between P1 and P2 such that its axis makes an angle 45o with that of P1. The intensity…2017 · MCQ
  • In a diffraction pattern due to a single slit of width a, the first minimum is observed at an angle 30o when light of wavelength 5000 A∘​ is incident on the slit. The first secondary maximum is observed at an…2016 · MCQ
  • The intensity at the maximum in a Young's double slit experiment is I0. Distance between two slits is d = 5λ, where λ is the wavelength of light used in the expreriment. What will be the intensity in front of one of the…2016 · MCQ
  • The interference pattern is obtained with two coherent light sources of intensity ratio n. In the interference pattern, the ratio Imax​+Imin​Imax​−Imin​​ will be2016 · MCQ
  • A linear aperture whose width is 0.02 cm is placed immediately in front of a lens of focal length 60 cm. The aparture is illuminated normally by a parallel beam of wavelength 5 × 10−5 cm. The distance of the first dark band of…2016 · MCQ