Home
Class 12
PHYSICS
An image of a bright square is obtained ...

An image of a bright square is obtained on a screen with the aid of a convergent lens. The distance between the square and the lens is 40cm. The area of the image is nine times larger than that of the square. Select the correct statement(s):

A

30 cm

B

50 cm

C

60 cm

D

75 cm

Text Solution

Verified by Experts

The correct Answer is:
A
`(A_i)/(A_0)=mu_2implies9m^2impliesm=+-3`
`u=-40cm,m=-3,m=(v)/(u)implies-3=(v)/(-40)`
`v=120cm`
`(1)/(f)=(1)/(v)-(1)/(u)=(1)/(120)-(1)/(-40)=(1+3)/(120)=(1)/(30)impliesf=30cm`
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

The image of an illuminated square object is obtained on a screen with the help of a converging lens. The distance of the square from the lens is 30 cm. The area of the image is 9 times of the square. What is the focal length of the ions ?

The image of a square hole in a screen illuminated by light is obtained on another screen with the help of converging lens. The distance of the hole from the lens is 40 cm. If the area of the image is nine times that of the hole, the focal length of the lens is

The real iamge of a square hole in screen, illuminated be light is obtained on another screen with the help of a converging lens. This distance of the hole from the lens is 20 cm. the are of the image is nine times that of the hole. What is the focal length of the lens ?

Try this Material: Convex lens, screen, metre scale, stand for the lens etc. Method: Keeping the screen fixed, obtain a clear image of a distant object like a tree or a building with the help of the lens on the screen. Measure the distance between the screen and the lens with the help of the metre scale. Now tum the other side of the lens towards the screen. Again obtain a clear image of the distant object on the screen by moving the lens forward or backward. Measure the distance between the screen and the lens again. What ls this distance between the lens and the screen called?

Try this Material: Convex lens, screen, metre scale, stand for the lens etc. Method: Keeping the screen fixed, obtain a clear image of a distant object like a tree or a building with the help of the lens on the screen. Measure the distance between the screen and the lens with the help of the metre scale. Now tum the other side of the lens towards the screen. Again obtain a clear image of the distant object on the screen by moving the lens forward or backward. Measure the distance between the screen and the lens again. What will happen if you use a concave lens in this experiment?

Try this Material: Convex lens, screen, metre scale, stand for the lens etc. Method: Keeping the screen fixed, obtain a clear image of a distant object like a tree or a building with the help of the lens on the screen. Measure the distance between the screen and the lens with the help of the metre scale. Now tum the other side of the lens towards the screen. Again obtain a clear image of the distant object on the screen by moving the lens forward or backward. Measure the distance between the screen and the lens again. Discuss the relation between this distance and the radius of curvature of the lens with your teacher.

The distance between the object and its real image from the convex lens is 60 cm and the height of image is two times the height of object . The focal length of the lens is

A sharp image of a distant object is obtained on a screen by using a convex lens. In order to determine the focal length of the lens, you need to measure the distance between the :

CP SINGH-REFRACTION AT SPHERICAL SURFACES-EXERCISES
  1. When an object is moved along the axis is of a lens images three times...

    Text Solution

    |

  2. The distance between two point object P and Q is 32 cm, a convex lens ...

    Text Solution

    |

  3. An image of a bright square is obtained on a screen with the aid of a ...

    Text Solution

    |

  4. A lens if placed between a source of light and a wall. It forms images...

    Text Solution

    |

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

    Text Solution

    |

  6. A converging beam of rays in incident on a diverging lens. Having pass...

    Text Solution

    |

  7. A cardsheet divided into squares each of size 1 mm^(2) is being viewed...

    Text Solution

    |

  8. Rays of light from Sun falls on a biconvex lens of focal length f and ...

    Text Solution

    |

  9. A boy is trying to start a fire by focusing sunlight on a piece of pap...

    Text Solution

    |

  10. The distance between an object and its real image formed by a convex l...

    Text Solution

    |

  11. A thin converging lens of focal length f is placed bewteen an obejct a...

    Text Solution

    |

  12. In the displacement method, a convex lens is placed in between an obje...

    Text Solution

    |

  13. The distance between the object and the screen is d (greater than 4 ti...

    Text Solution

    |

  14. In displacement method, the lengths of images in the two positions of ...

    Text Solution

    |

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

    Text Solution

    |

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

    Text Solution

    |

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

    Text Solution

    |

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

    Text Solution

    |

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

    Text Solution

    |

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

    Text Solution

    |