Home
Class 12
PHYSICS
A screen is placed a distance 40 cm away...

A screen is placed a distance 40 cm away from an illuminated object. A converging lens is palced between the source and the screen and it is attempted to form the image of the source on the screen. If no position could be found, the focal length of the lens

A

must be less than 10 cm

B

must be greater than 20 cm

C

must not be greater than 20 cm

D

must not be less then 10 cm

Text Solution

Verified by Experts

The correct Answer is:
B
`D=40cm`
For no position of lens `Dlt4f` i.e., `40lt4fimpliesfgt10cm`
The focal length should be greater than 10 cm
out of four options (2) is best option
Promotional Banner

Topper's Solved these Questions

  • REFRACTION AT SPHERICAL SURFACES

    CP SINGH|Exercise EXERCISES|105 Videos

  • REFLECTION OF LIGHT

    CP SINGH|Exercise EXERCISES|67 Videos

  • REFRACTION OF LIGHT BY PLANE SURFACES

    CP SINGH|Exercise Exercises|110 Videos

Similar Questions

Explore conceptually related problems

(a) A screen is kept at a distance of 1m from the object. A converging lens between the object and the screen, when placed at any of the two positions which are 60cm apart, forms a sharp image of the object on the screen. Find the focal length of the lens. (b) In the two positions of the lens, lateral size of the image is 4cm and 9cm. Find the size of the object.

A luminous object is placed at a distance of 40 cm from a converging lens of focal length 25 cm. The image obtained in the screen is

A luminous object is separated from a screen by distance d. A convex lends is placed between the object and the screeen such that it forms a distinct image on the screen. The maximum possible focal length of this convex lens is.

A source of light is located at a disatnce l = 90 cm from a screen. A thin converging lens provides the sharp image of the source when placed between the source of light and the screen at two positions. Determine the focal length o fthe lens if (a) the distance between the two positions of the lens is Delta l = 30 cm , (b) the transverse diamensions of the image at one position o fthe lens are eta = 4.0 greater than those at the pther position.

An illuminated object is placed at a distance of 20 cm from a converging lens of focal length 15 cm. The image obtained on the screen is:

CP SINGH-REFRACTION AT SPHERICAL SURFACES-EXERCISES
  1. In displacement method, the lengths of images in the two positions of ...

    Text Solution

    |

  2. The distance between an object and the screen is 100cm. A lens produce...

    Text Solution

    |

  3. A screen is placed a distance 40 cm away from an illuminated object. A...

    Text Solution

    |

  4. In an experiment with a lens the object distance u versus image distan...

    Text Solution

    |

  5. The graph between the object distance along the X-axis and image dista...

    Text Solution

    |

  6. The graps shows the variation of magnification m produced by as conve...

    Text Solution

    |

  7. In an optics experiment, with the position of the object fixed, a stud...

    Text Solution

    |

  8. A student measures the focal length of a convex lens by putting an obj...

    Text Solution

    |

  9. The graph between the lateral magnification (m) produced by a lens and...

    Text Solution

    |

  10. For a convex lens, if real image is formed the graph between (u+v) and...

    Text Solution

    |

  11. Diameter of a plano-convex lens is 6cm and thickness at the centre is ...

    Text Solution

    |

  12. An object is placed at a distance x1 from the principal focus of a len...

    Text Solution

    |

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

    Text Solution

    |

  14. An illuminated object is placed on the principal axis of a converging ...

    Text Solution

    |

  15. A split lens has its two parts separated by a and its focal length is ...

    Text Solution

    |

  16. When a biconvex lens of glass having refractive index 1.47 is dipped i...

    Text Solution

    |

  17. A convex lens if in contact with concave lens. The magnitude of the ra...

    Text Solution

    |

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

    Text Solution

    |

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

    Text Solution

    |

  20. A convex lens of focal length 40 cm a concave lens of focal length 40 ...

    Text Solution

    |