Home
Class 12
PHYSICS
Focal length of a convex lens of refract...

Focal length of a convex lens of refractive index 1.5 is 2 cm. Focal length of lens when immersed in a liquid of refractive index 1.25 will be

A

10 cm

B

2.5 cm

C

5 cm

D

7.5 cm

Text Solution

Verified by Experts

The correct Answer is:
C
`(f_(1))/(f_(a)) = (n_(ga) - 1)/( n_(gl) - 1) rArr (f_(1))/(2) = (1.5 - 1)/((1.5)/(1.25) - 1) rArr f_(1) = 5 `cm .
Promotional Banner

Topper's Solved these Questions

  • RAY OPTICS

    ERRORLESS|Exercise NCERT BASED QUESTIONS ( Prism Theory & Dispersion of Light )|46 Videos

  • RAY OPTICS

    ERRORLESS|Exercise NCERT BASED QUESTIONS ( Human Eye and Lens Camera )|15 Videos

  • RAY OPTICS

    ERRORLESS|Exercise NCERT BASED QUESTIONS ( Total internal reflection )|26 Videos

  • MAGNETISM

    ERRORLESS|Exercise Assertion and Reason|22 Videos

  • WAVE OPTICS AND ELECTROMAGNETIC THEORY

    ERRORLESS|Exercise ASSERTION & REASON |27 Videos

Similar Questions

Explore conceptually related problems

The focal length of a glass convex lens of refractive index 1.5 is 20 cm. What is the focal power of the lens when immersed in a liquid of refractive index of 1.25 ?

A thin convex lens of refractive index 1.5cm has 20cm focal length in air. If the lens in completely immersed in a liquid of refractive index. 1.6, then its focal length will be

A biconvex lens of refractive index "1.5" has a focal length of "20cm" in air.Its focal length when immersed in a liquid of refractive index "1.6" will be:

A thin converging lens made of glass of refractive index 1.5 acts as a concave lens of focal length 50 cm , when immersed in a liquid of refractive index 15//8 . Calculate the focal length of converging lens in air.

A lens is made of flint glass (refractive index =1.5 ). When the lens is immersed in a liquid of refractive index 1.25 , the focal length:

A corverging lens has a focal length of 20 cm in air. It is made of a material of refractive index 1.6 . If is immersed in a liquid of refractive index 1.3 , what will be its new focal length ?

ERRORLESS-RAY OPTICS-NCERT BASED QUESTIONS ( Refraction at Curved surface )
  1. In figure, an air lens of radius of curvature of each surface equal to...

    Text Solution

    |

  2. Two plano-concave lenses (1 and 2) of glass of refractive index 1.5 ha...

    Text Solution

    |

  3. Focal length of a convex lens of refractive index 1.5 is 2 cm. Focal l...

    Text Solution

    |

  4. A biconvex lens has a radius of curvature of magnitude 20cm. Which one...

    Text Solution

    |

  5. Let f(v) and f(r) are the focal lengths of a convex lens for violet an...

    Text Solution

    |

  6. A thin equi-convex lens is made of glass of refractive index 1.5 and i...

    Text Solution

    |

  7. A thin glass (refractive index 1.5) lens has optical power of -5D in a...

    Text Solution

    |

  8. A plano – convex lens made of material of refractive index mu with rad...

    Text Solution

    |

  9. A narrow parallel beam of light falls on a glass sphere of radius R an...

    Text Solution

    |

  10. The flat face of a plano-convex lens of focal length 10 cm is silvered...

    Text Solution

    |

  11. The focal length of a plano-convex lens is f and its refractive index ...

    Text Solution

    |

  12. A parallel beam of light is incident on a converging lens parallel to ...

    Text Solution

    |

  13. A convex lens of focal length f produces an image (1)/(n) times than ...

    Text Solution

    |

  14. The sun makes 0.5^(@) angle on earth surface. Its image is made by con...

    Text Solution

    |

  15. A convex lens of focal length f is placed somewhere in between an obje...

    Text Solution

    |

  16. An object placed at a distance of 16 cm from a convex lens produces an...

    Text Solution

    |

  17. An object has image thrice of its original size when kept at 8 cm and ...

    Text Solution

    |

  18. A square card of side length 1 mm is being seen through a magnifying l...

    Text Solution

    |

  19. A point object O is placed on the principal axis of a convex lens of f...

    Text Solution

    |

  20. Two point light sources are 24 cm apart. Where should a convex lens of...

    Text Solution

    |