Home
Class 12
PHYSICS
A contact combination is made of a thin ...

A contact combination is made of a thin convex lens (f = 9 cm) and a thin concave lens(f = 18 cm), the focal length of the combination is

A

6cm

B

12cm

C

18cm

D

27 cm

Text Solution

Verified by Experts

The correct Answer is:
C
Promotional Banner

Topper's Solved these Questions

  • Optics-I

    BINA LIBRARY|Exercise EXERCISE|154 Videos

  • OPTICS -II

    BINA LIBRARY|Exercise EXERCISE|84 Videos

  • QUESTION PAPER 2012

    BINA LIBRARY|Exercise EXERCISE|40 Videos

Similar Questions

Explore conceptually related problems

Two lenses of powers +5D and - 3D are in contact: Find the focal length of the combination.

Two lenses 3D and -1.5 D were put in contact. What is the focal length of the combination?

a convex lens of power 3.5D is placed in contact with a concave lens of power -1.5D. Find the effective focal length of the combination.

Two lenses of powers +5D and 3D are in contact.Find the focal length of combination.

Calculate the focal length of the combination of a convex lens of focal length 30 cm in contact with a concave lens of focal length 20 cm. Is the system a converging or diverging lens?

Find the power of a concave lens of focal length 2 m ?

A man used a concave lens of focal length 20cm.Find the power of the lens.

Two lenses of powers, 15D and +5D are in contact with each other forming a combination lens. What is the focal length of the combination?

BINA LIBRARY-Optics-I-EXERCISE
  1. What is the speed of light in glass of refractive index 1.5 if the vel...

    Text Solution

    |

  2. The refractive index of a medium is 1.8. A bubble lies in this medium ...

    Text Solution

    |

  3. When light travels from glass to air, there is no change in its

    Text Solution

    |

  4. The lateral shift produced in a parallel sided glass slab depends on

    Text Solution

    |

  5. What is optical fibres? What principle is used in it?

    Text Solution

    |

  6. The refractive index of an equilateral prism is 'sq.root 3' . What is ...

    Text Solution

    |

  7. The minimum distance between an object and its real image is

    Text Solution

    |

  8. Critical angle of light passing from glass to air is minimum for

    Text Solution

    |

  9. The critical angle for a medium is 60°. Then the refractive index of t...

    Text Solution

    |

  10. In which of the following cases total internal reflection can not be o...

    Text Solution

    |

  11. The distance between the object and its real image formed by a convex ...

    Text Solution

    |

  12. The focal length of a lens depends upon

    Text Solution

    |

  13. A contact combination is made of a thin convex lens (f = 9 cm) and a t...

    Text Solution

    |

  14. Two thin lenses of focal length 20 cm and 25 cm are placed in contact....

    Text Solution

    |

  15. A lens behaves as a converging lens in air and a diverging lens in wat...

    Text Solution

    |

  16. An eye has a defect of myopia if it does not see

    Text Solution

    |

  17. For removal of hypermetropia, one should use

    Text Solution

    |

  18. On increasing the tube-length of a compound microscope its magnifying ...

    Text Solution

    |

  19. A sharp image is observed through a compound microscope. Now if the ey...

    Text Solution

    |

  20. A convex lens of focal length 10 cm is used as a simple microscope. It...

    Text Solution

    |