Home
Class 12
PHYSICS
A convex lens of focal length 20cm and a...

A convex lens of focal length 20cm and a concave lens of focal length f are mounted coaxially 5cm apart. Parallel beam of light incident on the convex lens emerges from the concave lens as a parallel beam. Then, f in cm is

A

35

B

25

C

20

D

15

Text Solution

Verified by Experts

The correct Answer is:
d.
Clearly, power of system is zero.
`:.0=(1)/(20)+(1)/(f)-(5)/(20f)`
or `-(1)/(20)=(15)/(20f) or f=-15cm`
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 convex lens of focal length 1.0m and a concave lens of focal length9.25m are 0.75m apart. A parallel beam of light is incident on the convex lens. The beam emerging after refraction from both lenses is

A convex lens of focal length 10cm and concave lens of focal length 20 cm are kept 5 cm apart. The focal length of the equivalent lens is

A convex lens of focal length 25 cm and a concave lens of focal length 10 cm are joined together. The power of the combination will be

A convex lens of focal length 80 cm and a concave lens of focal length 50 cm are combined toghether. What will be their resulting power ?

A thin convex lens of focal length 10 cm and a thin concave lens of focal length 26.2 cm are in contact. The combination acts as

A convex lens of focal length 1 meter and a concave lens of focal length 0.25 meter are kept 0.75 meter apart. A parallel beam of light first passes throught the convex lens, then through the concave lens and comes to a focus 0.5 m away from the the concave lens.

A convex lens of focal length 1 meter and a concave lens fo focal length 0.25 meter and kept 0.75 meter apart. A parallel beam of light first passes through the ocnvex lens, then through the concave lens and comes to a focus 0.5m away from the concave lens.

A convex lens of focal length 25 cm and a concave lens of focal length 20 cm are mounted coaxially separated by a distance d cm . If the power of the combination is zero, d is equal to

CENGAGE PHYSICS-GEOMETRICAL OPTICS-Single Correct
  1. A hollow double concave lens is made of very thin transparent materia...

    Text Solution

    |

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

    Text Solution

    |

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

    Text Solution

    |

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

    Text Solution

    |

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

    Text Solution

    |

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

    Text Solution

    |

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

    Text Solution

    |

  8. Refraction takes place at a convex spherical boundary separating glass...

    Text Solution

    |

  9. The image of point P when viewd from top of the slabs will be

    Text Solution

    |

  10. The refractive index of a prism is 2. The prism can have a maximum ref...

    Text Solution

    |

  11. One of the refracting surfaces of a prism of angle 30^(@) is silvered...

    Text Solution

    |

  12. Angle of minimum deviation is equal to the angle of prism A of an equi...

    Text Solution

    |

  13. A plano-convex lens fits exactly into a plano-concave lens. Their plan...

    Text Solution

    |

  14. A parallel beam of light is incident on the system of two convex lense...

    Text Solution

    |

  15. A point object is placed at a distance of 25 cm from a convex lens of ...

    Text Solution

    |

  16. A convex lens of focal length 10cm is painted black at the middle port...

    Text Solution

    |

  17. A cubic container is filled with a liquid whose refractive index incre...

    Text Solution

    |

  18. A lens forms a virtual, diminished image of an object placed at 2m fro...

    Text Solution

    |

  19. Two convex lenses placed in contact form the image of a distant object...

    Text Solution

    |

  20. An equiconvex lens is cut into two halves along (i) XOX^(') and (ii) Y...

    Text Solution

    |