Home
Class 12
PHYSICS
If a person can sees clearly at a distan...

If a person can sees clearly at a distance of 100 cm, then find the power of leris used to see object at 40 cm.

Text Solution

Verified by Experts

By lens formula,
`1/f=1/v-1/u` ltbr. Given,v=-100 cm and u=-40 cm
`therefore 1/f=1/100-1/(-40)rArr1/f=-1/100+1/40`
`rArr1.f=(-1+2.5)/100=1.5/100`
Hence, power of lens is
`P=100/(f(cm))=100xx1.5/100=1.5D`
Promotional Banner

Topper's Solved these Questions

  • RAY OPTICS

    DC PANDEY|Exercise Checkpoint 9.1|10 Videos

  • RAY OPTICS

    DC PANDEY|Exercise Checkpoint 9.2|10 Videos

  • NUCLEI

    DC PANDEY|Exercise C MADICAL ENTRANCES GALLERY|46 Videos

  • REFLECTION OF LIGHT

    DC PANDEY|Exercise Subjective|9 Videos

Similar Questions

Explore conceptually related problems

A nearsighted person cannot clearly see beyond 200 cm. Find the power of the lens needed to see objects at large distances.

(a) A nearsighted person cannot clearly see beyond 200 cm . Find the power of the lens needed to see objectes at large distances. (b) A farsighted person cannot see objects placed closer to 50cm . Find the power of the lens needed to see the objets at 20cm . (c) A person wears glasses of power -2.5 D . Is the person farsighted or nearsighted? What is the far point of the person without the glasses?

A farsighted person cannot see objects placed closer to 50 cm. Find the power of the lens needed to see the objects at 20 cm.

A far-sighted man can see clearly at a distance of 1.0m . The power of the lens that would make him see clearly at a distance of 0.2m is

A person can not see clearly an object kept at a distance beyond of 100 cm. Find the nature and the power of lens to be used for seeing clearly the object at infinity.

A person can see objects clearly from a distance 10cm to infinity.Then we can say that the person is

DC PANDEY-RAY OPTICS-Medical entrance gallary
  1. If a person can sees clearly at a distance of 100 cm, then find the po...

    Text Solution

    |

  2. Two identical glass (mu(g)=3//2) equi- convex lenses of focal length f...

    Text Solution

    |

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

    Text Solution

    |

  4. A person can see clearly objects only when they lie between 50 cm and ...

    Text Solution

    |

  5. An astronomical telesope has objective and eyepiece of focal lengths 4...

    Text Solution

    |

  6. Match the corresponding entries of Column I with Column II.

    Text Solution

    |

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

    Text Solution

    |

  8. Two identical thin planoconvex glass lenses (refractive index 1.5) eac...

    Text Solution

    |

  9. The refracting angle of a prism is A and refractive index of the mater...

    Text Solution

    |

  10. The near point and far point of a person are 40cm and 250cm, respectiv...

    Text Solution

    |

  11. An object is seen thorugh a simple microscope of focal length 12 c. Fi...

    Text Solution

    |

  12. Angle of minimum deviation for a prism of refractive index 1.5 is equa...

    Text Solution

    |

  13. A ray of light passes from a medium A having refractive index 1.6. to ...

    Text Solution

    |

  14. The focal length of a converting lens are f(v) and f(r) for violet and...

    Text Solution

    |

  15. Aperture of human eye is 0.2cm. The minimum magnifying power of a visa...

    Text Solution

    |

  16. An object is located 4cm from the first of two thin converging lenses ...

    Text Solution

    |

  17. If mu(v)=1.530 and mu(R)=1.5145, then disperisve power of a crown glas...

    Text Solution

    |

  18. Disperion of light is caused due to

    Text Solution

    |

  19. Calculate the focal length of a reading glass of a person, if the dist...

    Text Solution

    |

  20. A person wants a real image of his own, 3 times enlarged. Where should...

    Text Solution

    |

  21. The magnification power of a convex lens of focal length 10cm, when th...

    Text Solution

    |