Home
Class 12
PHYSICS
A lens forms a real image of an object. ...

A lens forms a real image of an object. The distance from the object to the lens is x cm and that from the lens to the image is y cm. The graph shows the variation of y with x.
It can be deduced that the lens is

A

converging and of focal length 10cm

B

converging and of focal length 20cm

C

converging and of focal length 40cm

D

diverging and of focal length 20cm

Text Solution

Verified by Experts

The correct Answer is:
a.
A diverging lens is ruled out because both x and y are positive values. Both x and y equal 20cm at their smalles su, which occurs when
` x+y=40cm=4f`
`:. f=10cm`
This indicates a converging lens of focal length `= 10cm`
Promotional Banner

Topper's Solved these Questions

  • GEOMETRICAL OPTICS

    CENGAGE PHYSICS|Exercise Assertion-Reasoninig|2 Videos

  • GEOMETRICAL OPTICS

    CENGAGE PHYSICS|Exercise Linked Comprehension|51 Videos

  • GEOMETRICAL OPTICS

    CENGAGE PHYSICS|Exercise Subjective|26 Videos

  • FRICTION

    CENGAGE PHYSICS|Exercise QUESTION BANK|1 Videos

  • GRAVITATION

    CENGAGE PHYSICS|Exercise Question Bank|39 Videos

Similar Questions

Explore conceptually related problems

A lens forms a real image 3 cm high of an object 1 cm high. If the separation of object and image is 15 cm, find the focal length of the lens.

A lens forms real image of an object 20 cm away from lens. A second lens is kept in contact with this lens, then image shifts 10 cm towards the lens combination. Find the power of another lens.

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 convex lens produces a real image m times the size of the object. What will be the distance of the object from the lens ?

A convex lens of focal length 16 cm forms a real image double the size of the object. The image distance of the object from the lens is

A convex lens forms a real image on a screen placed at a distance 60 cm from the object. When the lens is shifted towards the screen by 20 cm , another image of the object is formed on the screen. The focal length of the lens is :

A convex lens forms an image of an object on a screen 30 cm from the lens. When the lens is moved 90 cm towards the object, then the image is again formed on the screen. Then, the focal length of the lens is

A lens forms a virtual image 4 cm away from it when an object is placed 10 cm away from it. The lens is a ….. Lens of focal length ……………

CENGAGE PHYSICS-GEOMETRICAL OPTICS-Single Correct
  1. A plano-convex lens when silvered ono the plane side behaves like a co...

    Text Solution

    |

  2. Two thin lenses are placed 5cm apart along the same axis and illuminte...

    Text Solution

    |

  3. A lens forms a real image of an object. The distance from the object t...

    Text Solution

    |

  4. A plastic hemisphere has a radius of curvature of 8cm and an index of ...

    Text Solution

    |

  5. A ray of light falls on a transparent sphere with center at C as shown...

    Text Solution

    |

  6. A circular beam of light of diameter d = 2 cm falls on a plane refract...

    Text Solution

    |

  7. Critical angle of glass is theta(1) and that of water is theta(2). The...

    Text Solution

    |

  8. Light is incident normally on face AB of a prism as shown in Figure. A...

    Text Solution

    |

  9. A ray of light is incident on a glass sphere of refractive index 3//2 ...

    Text Solution

    |

  10. Two identical glass (mu(g)=3//2) equiconvex lenses of focal length f a...

    Text Solution

    |

  11. An object is kept at a distance of 16 cm from a thin lens and the imag...

    Text Solution

    |

  12. Point object O is placed on the principal axis of a convex lens of foc...

    Text Solution

    |

  13. Light of wavelength 500nm traveling with a speed of 2.0xx10^(8)ms^(-1)...

    Text Solution

    |

  14. A hollow double concave lens is made of very thin transparent materia...

    Text Solution

    |

  15. The velocity of light in a medium is half its velocity in air. If a ra...

    Text Solution

    |

  16. A convex lens of focal length 20cm and a concave lens of focal length ...

    Text Solution

    |

  17. An equiconvex lens is made from glass of refractive index 1.5. If the ...

    Text Solution

    |

  18. An object is put at a distance of 5cm from the first focus of a convex...

    Text Solution

    |

  19. A luminous object is placed 20 cm from surface of a convex mirror and ...

    Text Solution

    |

  20. Consider the situation shown in figure. Water (mu=4//3) is filled in a...

    Text Solution

    |