Home
Class 11
PHYSICS
A screen is placed 90 cm from an object....

A screen is placed 90 cm from an object. The image an object on the screen is formed by a convex lens two different locations separated by 20 cm. the focus length of the lense is

A

`20.4 cm`

B

`21.4 cm`

C

`22.5 cm`

D

`28.5 cm`

Text Solution

Verified by Experts

The correct Answer is:
B
Promotional Banner

Topper's Solved these Questions

  • RAY OPTICS

    TARGET PUBLICATION|Exercise COMPETITIVE THINKING|68 Videos

  • RAY OPTICS

    TARGET PUBLICATION|Exercise EVALUATION TEST|16 Videos

  • RAY OPTICS

    TARGET PUBLICATION|Exercise EVALUATION TEST|16 Videos

  • OPTICS

    TARGET PUBLICATION|Exercise EXERCISE|447 Videos

  • REFRACTION OF LIGHT

    TARGET PUBLICATION|Exercise EVALUATION TEST|15 Videos

Similar Questions

Explore conceptually related problems

The real image of an object placed at 60 cm from a concave Mirror is formed at 20 cm. from the mirror. Find the focal length of the mirror.

An object is kept at 10 cm in front of a convex lens . Its image is formed on the screen at 15 cm from the lens. Calculate (i) the focal length of the lens (ii) the magnification produced by the lens.

An object is placed at a distance of 10cm from a convex lens of focal length 12cm.Find the position and nature of the image.

Solve the following examples/ numerical problems: An object is kept at 60 cm in front of a convex lens. Its real image is formed at 20 cm from the lens . Find the focal length of the lens.

An object of height 2 cm is kept at 30 cm from a convex lens . Its real image is formed at 60 cm from the lens .Find the focal length and power of the lens.

when an object is kept in frnt of a convex lens the distance between it and the real image is 54 cm. if the magnification produced is 2, the focal length of the lens is

Solve the following examples/ numerical problems: When a pin of height 3 cm is fixed at 10 cm from a convex lens , the height of the virtual image formed is 12 cm . Find the focal length of the lens.

A convex lens forms a real and inverted image of a pencil at a distance of 40 cm from the lens. The image formed is of the same size as the object Find the focal length and power of the lens. At what distance is the : object placed from the lens?

The distance between an object and the screen is 75 cm. When a convex lens of focal length 12 cm is placed in the between theobject and the screen, magnification of real formed can be (magnitude only)

An object is placed vertically at a distance of 20 cm from a convex lens .If the height of the object is 5 cm and the focal length of the lens is 10 cm, what will be the position, size and nature of the image? How much bigger will the image be as compared to the object?

TARGET PUBLICATION-RAY OPTICS-CRITICALTHINKING
  1. The power of a thin convex lens (""(a) mu(g)=1.5) is +5.0 D. When it i...

    Text Solution

    |

  2. Figure given below shows a beam of light converging at point P. When a...

    Text Solution

    |

  3. A screen is placed 90 cm from an object. The image an object on the sc...

    Text Solution

    |

  4. When two thin lenses are kept in contanct, the focal length of the com...

    Text Solution

    |

  5. As shown in the figure, the liquids L1, L2 and L3 have refractive indi...

    Text Solution

    |

  6. When two or more lnses of magnification m(1) ,m(2), m(3) are kept in c...

    Text Solution

    |

  7. A concave lens and a convex lens have same focal length of 20 cm and b...

    Text Solution

    |

  8. If we need a magnification of 400 from compound microscope of tube len...

    Text Solution

    |

  9. When objects at different distances are seen by the eye, which of the ...

    Text Solution

    |

  10. If astronomical telescope of length 1.53m has magnifying powerof magni...

    Text Solution

    |

  11. When we view object of height 15 m with a telescop of magnifying power...

    Text Solution

    |

  12. The focal length of the objective and eye piece of a telescope are res...

    Text Solution

    |

  13. The objective of telescope A has a diameter 3 times that of the object...

    Text Solution

    |

  14. A fly is sitting on the objective of a telescop pointed to the moon ta...

    Text Solution

    |

  15. An object is placed at a distance u from a concave mirror and its real...

    Text Solution

    |

  16. The distance between an object and the screen is 75 cm. When a convex ...

    Text Solution

    |

  17. Two similar planoconvex lenses are combined together in three differen...

    Text Solution

    |

  18. A virtual cannot be caought on a screen, Yet when we see a virtual ima...

    Text Solution

    |

  19. When the wavelenght of the light used is increased, the focal length o...

    Text Solution

    |

  20. If two power of a thick lense is P(1) and that of a thin lens is P(2)...

    Text Solution

    |