Home
Class 12
PHYSICS
A convex lens is placed in contact with ...

A convex lens is placed in contact with a plane mirror. An axial point object at a distance of `20 cm` from this combination, has its image coinciding with itself. What is the focal length of the convex lens ?

Text Solution

Verified by Experts

If light rays become parallel to principal axis then they will fall normally on plane mirror. Hence object is kept at focus of lens. Focal length of lens = 20 cm.
Promotional Banner

Topper's Solved these Questions

  • RAY OPTICS AND OPTICAL INSTRUMENTS

    MODERN PUBLICATION|Exercise Revision Exercises (Additional Questions)|22 Videos

  • RAY OPTICS AND OPTICAL INSTRUMENTS

    MODERN PUBLICATION|Exercise Revision Exercises (Fill in the Blanks)|10 Videos

  • RAY OPTICS AND OPTICAL INSTRUMENTS

    MODERN PUBLICATION|Exercise Higher Order Thinking Skills & Advanced Level (QUESTIONS WITH ANSWERS)|20 Videos

  • NUCLEI

    MODERN PUBLICATION|Exercise CHAPTER PRACTICE TEST FOR BOARD EXAMINATION|15 Videos

  • SEMICONDUCTOR ELECTRONICS METERIALS DEVICES AND SIMPLE CIRCUITS

    MODERN PUBLICATION|Exercise CHAPTER PRACTICE TEST FOR BOARD EXAMINATION|12 Videos

Similar Questions

Explore conceptually related problems

A convex lens and a convex mirror of radius of curvature 20 cm are placed co-axially with the convex mirror placed at a distance of 30 cm from the lens. For a point object at a distance of 25 cm from the lens, the final image due to this combination coincides with the object itself. What is the focal length of convex lens ?

A convex lens and a convex mirror of radius of curvature 20 cm are placed co-axially with the convex mirror placed at a distance of 30 cm from the lens. For a point object at a distance of 25 cm from the lens, the final image due to this combination coincides with the object itself. What is the focal length of convex lens ? (NCERT Solved Example)

A convex lens is coaxially placed with a concave lens. A screen is placed at a distance of 100 cm apart from the combination. The focal length of convex lens is 15 cm. Determine the focal length of the concave lens if image of object placed at a distance of 20 cm, from the combination, is projected on the scrcen.

A thin convex lens of focal length 30 cm is placed in front of a plane mirror. An object is placed at a distance x from the lens (not in between lens and mirror ) so that its final image coincides with itself. Then, the value of x is

A convex lens of focal length 15 cm is placed on a plane mirror. An object is placed at 30 cm from the lens. The image is

Ray coming from an object situated at infinity, fall on a convex lens and an image is formed at a distance of 16 cm from the lens. When a concave lens is kept in contact with the convex lens, the image is formed at a distance of 20 cm from the lens combination. Calculate the focal length of the concave lens.

A 20cm convex lens is placed in contact with a diverting lens of unknown focal length ,The lens combination acts as a converging lens and has a length of 30cm .What is the focal length of the diverging lens.

A convex lens of focal length 15 cm is placed on a plane mirror. An object is placed 20 cm from the lens. The image is formed

MODERN PUBLICATION-RAY OPTICS AND OPTICAL INSTRUMENTS-Revision Exercises (Very Short Answer Questions)
  1. A substance has critical angle of 45^(@) for yellow light. What is its...

    Text Solution

    |

  2. If (sini)/(sinr)=n(21)gt1. Out of medium 1 and medium 2, which is mor...

    Text Solution

    |

  3. A convex lens is placed in contact with a plane mirror. An axial point...

    Text Solution

    |

  4. A biconcave lens made of a transparent material of refractive index 1...

    Text Solution

    |

  5. The radii of curvature of both the surfaces of a convex lens are equal...

    Text Solution

    |

  6. Two thin lenses of power +6 D and -2 D are in contact. What is the foc...

    Text Solution

    |

  7. For the same value of angle of incidence, the angles of refraction in ...

    Text Solution

    |

  8. When red light passing through a convex lens is replaced by light of b...

    Text Solution

    |

  9. A glass lens of refractive index 1.5 is placed in a trough of liquid. ...

    Text Solution

    |

  10. Your are given following three lense. Which two lenses will you use as...

    Text Solution

    |

  11. Does the critical angle depend on the wavelength of the light ?

    Text Solution

    |

  12. Due to which phenomenon, advanced sunrise and delayed sunset occur ?

    Text Solution

    |

  13. What will be the effect on the power of a glass lens if it is immersed...

    Text Solution

    |

  14. Define one dioptre.

    Text Solution

    |

  15. Find the focal length of a lens having -0.5 D power.

    Text Solution

    |

  16. What is total internal reflection of light ? What are conditions for t...

    Text Solution

    |

  17. What are optical fibres ? What is the principle on which optical fibre...

    Text Solution

    |

  18. What is the main requirement in fabricating optical fibres ?

    Text Solution

    |

  19. What are para-axial rays and marginal rays ?

    Text Solution

    |

  20. Under what condition will the object and image always be on the same s...

    Text Solution

    |