Home
Class 12
PHYSICS
The angle of a prism is A. One of its re...

The angle of a prism is A. One of its refracting surfaces is silvered. Light rays falling at an angle of incidence 2A on the first surface re turns back through the same path after suffer ing reflection at the silvered surface. The re fractive index m of the prism is

A

2 sin A

B

2 cos A

C

`1/2` cos A

D

tan A

Text Solution

Verified by Experts

The correct Answer is:
A, B, C
In `A=r_1+r_2,r_1=r` and `r_2=0 therefore A=r`
From Snell.s law, `n_1sini=n_2sin r`
(1) sin2A=nsinA
`thereforen=(sin2A)/(sinA)`
`=(2sinAcosA)/(sinA)=2cosA`
Promotional Banner

Topper's Solved these Questions

  • RAY OPTICS AND OPTICAL INSTRUMENTS

    KUMAR PRAKASHAN|Exercise SECTION-D (MULTIPLE CHOICE QUESTIONS (MCQs))(MCQs FROM .DARPAN. BASED ON TEXTBOOK)(MCQs BASED ON TEXTUAL ILLUSTRATION AND EXERCISE)|24 Videos

  • MOVING CHARGES AND MAGNETISM

    KUMAR PRAKASHAN|Exercise SECTION D (MCQs ASKED IN COMPETITIVE EXAMS)|34 Videos

  • SAMPLE QUESTION PAPER

    KUMAR PRAKASHAN|Exercise PART-B SECTION-C|5 Videos

Similar Questions

Explore conceptually related problems

At what angle should a ray of light be incident on the face of a prism of refracting angle 60^(@) so that it just suffers total internal reflection at the other face? The refractive index of the material of the prism is 1.524.

The refractive index of the material of a prism is sqrt2 and the angle of the prism is 30^@ . One of the two refracting surfaces of the prism is made a mirror inwards, by silver coating. A beam of monochromatic light entering the prism from the other face will retrace its path (after reflection from the silvered surface) if its angle of incidence on the prism is

The angle of incidence for a ray of light at a refracting surface of a prism is 45^@ . The angle of prism is 60^@ . If the ray suffers minimum deviation through the prism, the angle of minimum deviation and refractive index of the material of the prism respectively, are

A direct-vision prism is made out of three prisms, each with a refracting angle of phi=60^(@) , attached to each other as shown in Figure. Light of a certain wavelength is incident on the first prism. The angle of incidence is 30^(@) and the ray leaves the third prism parallel to the direction of incidence. The refractive index of the glass of the first and third prisms, is 1.5. Find the refractive index of the material of the middle prism. (sqrt(6)=2.45)

Two mirrors are inclined at angle theta as shown in figure. Light rays are incident parallel to one of mirrors. Light will start retracing its path after the reflection if

The diagram shows five isosceles right angled prisms.A light ray incident at 90^(@) at the first face emerge at same angle with the normal from the last face.Which of the following relations will hold regarding the refractive indices?

Refractive index of a prism is root_2 . One side of prism is polished, if ray incidences at ......, then it will return back to its original path, refraction angle is 30^@

A ray of light is incident on liquid surface such that reflected and refracted ray are perpendicular to each other. If refractive index is 1.4, find angle of incident.

For right-angled prism, ray-1 is the incident ri and ray-2 is the emergent ray as shown in the figure. Refractive index of the prism is .........

A ray of light is incident on the surface of a glass plate at an angle of incidence equal to Brewster's angle phi . If mu represents the refractive index of glass with respect to air, then the angle between reflected and refracted rays is

KUMAR PRAKASHAN-RAY OPTICS AND OPTICAL INSTRUMENTS-SECTION-D (MULTIPLE CHOICE QUESTIONS (MCQs))(MCQs ASKED IN COMPETITIVE EXAMS)
  1. A converging light beam incidents on diverging lens. After passing thr...

    Text Solution

    |

  2. A plano convex lens fits exactly into a plano concave lens. Their plan...

    Text Solution

    |

  3. The angle of a prism is A. One of its refracting surfaces is silvered....

    Text Solution

    |

  4. Two identical thin plano-convex glass lenses (refractive index 1.5) ea...

    Text Solution

    |

  5. The refracting angle of a prism is A and refrac tive index of the mate...

    Text Solution

    |

  6. In an astronomical telescope in normal adjustment a straight black lin...

    Text Solution

    |

  7. A beam of light consisting of red, green and blue colours is incident ...

    Text Solution

    |

  8. Match the corresponding entries of column-1 with column-2. (Where m is...

    Text Solution

    |

  9. The angle of incidence for a ray of light at a refracting surface of a...

    Text Solution

    |

  10. Two identical glass (mug=3/2) equiconvex lenses of focal length f each...

    Text Solution

    |

  11. An air bubble in a glass slab with refractive index 1.5 (near normal i...

    Text Solution

    |

  12. If the angle of a prism is 60° and angle of minimum deviation is 40°, ...

    Text Solution

    |

  13. A light beam is incident on a denser medium whose refractive index is ...

    Text Solution

    |

  14. If power of objective lens increases, then magnifying power…......

    Text Solution

    |

  15. A astronomical telescope has objective and eyepiece of focal length 40...

    Text Solution

    |

  16. A beam of light from a source L is incident normally on a plane mirror...

    Text Solution

    |

  17. A prism of refractive index mu1 = 1.42 and prism angle 10° is arranged...

    Text Solution

    |

  18. An object is placed at a distance of 40 cm from a concave mirror of fo...

    Text Solution

    |

  19. The refractive index of the material of a prism is sqrt2 and the angle...

    Text Solution

    |

  20. Pick the wrong answer in the context with rainbow.

    Text Solution

    |