Home
Class 12
PHYSICS
To ensure almost 100% transmittivity, ph...

To ensure almost `100%` transmittivity, photographic lenses are often coated with a thin layer of dielectric maerial, like `MgF_(2)(mu=1.38)` . The minimum thickness of the film to be used so that at the centre of visible spectrum `(lambda = 5500 Å)` there is maximum transmission.

A

`1000Å`

B

`2000Å`

C

`4000Å`

D

500Å`

Text Solution

Verified by Experts

The correct Answer is:
A
for interfrence at thin films `(2mu cosd r) = (lambda)/(2)`
Here `i~~r~~0`
`:. T = (lambda)/(4mu)`
Promotional Banner

Topper's Solved these Questions

  • WAVE OPTICS

    NARAYNA|Exercise LEVEL - V|37 Videos

  • WAVE OPTICS

    NARAYNA|Exercise LEVEL - VI|40 Videos

  • WAVE OPTICS

    NARAYNA|Exercise LEVEL - III|30 Videos

  • SEMICONDUCTOR ELECTRONICS

    NARAYNA|Exercise ADDITIONAL EXERCISE (ASSERTION AND REASON TYPE QUESTIONS :)|19 Videos

Similar Questions

Explore conceptually related problems

On face of a glass (mu = 1.50) lens is coated with a thin film of magnesium fluoride MgF_(2)(mu = 1.38) to reduce reflection from the lens surface. Assuming the incident light to be perpendicular to the lens surface. The least coating thickness that eliminates the reflection at the centre of the visible spectrum (lamda = 550 nm) is about

A glass lens is coated on one side with a thin film of magnesium fluoride (MgF_(2)) to reduce reflection from the lens surface (Fig. 2.26). The Index of refraction of MgF_(2) is 1.38, that of the glass is 1.50. What is the least coating thickness that eliminates (via interference) the reflections at the middle of the visible specturm (lambda = 550nm) ? Assume that the light is approxmately perpendicular to the lens surface.

In the YDSE, the monochromatic source of wavelength lambda is placed at a distance d/2 from the central axis (as shown in the figure), where d is the separation between the two slits S_1 and S_2 . (a)Find the position of the central maxima. (b) Find the order of interference formed at O. (c)Now, S is placed on centre dotted line. Find the minimum thickness of the film of refractive indes mu =1.5 to be placed in front of S_2 so that intensity at O becomes 3/4 th of the maximum intensity. (Take lambda=6000Å, d = 6mm .)

In solar cells, a silicon solar cell (mu = 3.5) is coated with a thin film of silicon monoxide SiO (mu = 1.45) to minimize reflective losses from the surface. Determine the minimum thickness of SiO that produces the least reflection at a wavelength of 550nm, near the centre of the visible spectrum. Assume approximately normal incidence .

A lens ( mu=1.5 ) is coated with a thin film of refractive index 1.2 order to reduce the reflected form its surface at lambda=4800Å .Find the maximum thickness of the film which will minimized the intensity of the reflected light .(Assume near normal incidence)

A thin film of a specific meterial can be used to decrease the intensity of reflected light. There is destrucive inteference of wave reflected from upper and lower surface of the film. These films are called non-reflecting or anti-reflecting coatings. The process of coating the lens or surface with non-reflecting film is called blooming as shown in figure The refracting index of coating (n_(1)) is less than that of the glass (n_(2)) . 5. magnesium fluoride (MgF_(2)) is generally use as anti-reflection coating. If refractive index of MgF_(2) is 1.25, then minimum thickness of film required is (Take lambda = 500 nm )

To produce a minimum reflection of wavelength near the middle of visible spectrum (550 nm), how thick should a coating of MgF_(2) (mu = 1.38) be vaccum-coated on a glass surface?

A thick glass slab (mu= 1.5) is to be viewed in reflected white light. It is proposed to coat the slab with a thin layer of a material having refractive index 1.3 so that the wavelength 6000 Å os suppressed. Find the minimum thickness of the coating required.

NARAYNA-WAVE OPTICS-NCERT Based Questions
  1. Choose the correct statement

    Text Solution

    |

  2. Consider a point at the focal point of a convex lens. Another convex l...

    Text Solution

    |

  3. The human eye has an approximate angular resolution of phi = 5.8xx10^(...

    Text Solution

    |

  4. For the same objective, the ratio of least separation between two poin...

    Text Solution

    |

  5. In a YDSE arrangement, the distance of screen from the slits is half t...

    Text Solution

    |

  6. Two source S(1) and S(2) of intensity I(1) and I(2) are placed in fron...

    Text Solution

    |

  7. Consider sunlight incident on a pinhole of width 10^(3)Å. The image of...

    Text Solution

    |

  8. Consider the diffraction patern for a small pinhole. As the size of th...

    Text Solution

    |

  9. For light diverging from a point source

    Text Solution

    |

  10. A polariod (I) is placed in front of a monochromatic source. Another p...

    Text Solution

    |

  11. As shown in figure a two slit arrangement with a source (S) which emit...

    Text Solution

    |

  12. Four identical monochromatic source A, B, C, D as shown in figure prod...

    Text Solution

    |

  13. To ensure almost 100% transmittivity, photographic lenses are often co...

    Text Solution

    |

  14. A small transparent slab (mu = 1.5) is placed along AS(2) as shown. ...

    Text Solution

    |

  15. A small transparent slab (mu = 1.5) is placed along AS(2) as shown. ...

    Text Solution

    |

  16. A small transparent slab (mu = 1.5) is placed along AS(2) as shown. ...

    Text Solution

    |

  17. The optical properties of a medium are governed by the relative permit...

    Text Solution

    |

  18. The optical properties of a medium are governed by the relative permit...

    Text Solution

    |

  19. Statement - I : Diffraction of sound waves is evident in daily experin...

    Text Solution

    |

  20. Statement - I : Reflection results in plane front the side with higher...

    Text Solution

    |