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

2017 · Q123
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. /2017 · Q123

Wave Optics question

2017 · Q123

NEETPhysicsWave OpticsMCQ+4 / −1
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 nearly
  1. A
    1.59
  2. B
    1.69
  3. C
    1.78
  4. D
    1.25
View written solutionFree

Correct answer: C

Position of 8th bright fringe in medium

x = 8λmDμd{{8{\lambda _m}D} \over {\mu d}}μd8λm​D​

Position of 5th dark fringe in air,

x' = (5−12)λairDd{{\left( {5 - {1 \over 2}} \right){\lambda _{air}}D} \over d}d(5−21​)λair​D​ = 4.5λairDd{{4.5{\lambda _{air}}D} \over d}d4.5λair​D​

According to question

8λmDμd{{8{\lambda _m}D} \over {\mu d}}μd8λm​D​ = 4.5λairDd{{4.5{\lambda _{air}}D} \over d}d4.5λair​D​

⇒\Rightarrow⇒ μ\mu μ = 1.78

PreviousNext

More from Wave Optics

  • 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
  • At the first minimum adjacent to the central maximum of a single-slit diffraction pattern, the phase difference between the Huygen's wavelet from the edge of the slit and the wavelet from the midpoint of the slit is2015 · MCQ
  • Two slits in Young's experiment have widths in the ratio 1 : 25. The ratio of intensity at the maxima and minima in the interference pattern, Imin​Imax​​ is2015 · MCQ