Home
Class 12
PHYSICS
A plano-convex lens (f = 20 cm) is silve...

A plano-convex lens `(f = 20 cm)` is silvered at plane surface. The focal length will be

A

20 cm

B

40 cm

C

30 cm

D

10 cm

Text Solution

Verified by Experts

The correct Answer is:
D
(d) The focal length of the plano-convex lens is 20 cm with the plane surface bieng silvered.
So, the net power of the lens is given by
`P=1/fxx2=2/f`
Thus, the net focal length is, `f/2=20/2=10 cm`
Promotional Banner

Topper's Solved these Questions

  • RAY OPTICS

    DC PANDEY ENGLISH|Exercise medical entrance special format question|23 Videos

  • RAY OPTICS

    DC PANDEY ENGLISH|Exercise Medical entrance gallary|76 Videos

  • RAY OPTICS

    DC PANDEY ENGLISH|Exercise Checkpoint 9.7|10 Videos

  • NUCLEI

    DC PANDEY ENGLISH|Exercise C MADICAL ENTRANCES GALLERY|46 Videos

  • REFLECTION OF LIGHT

    DC PANDEY ENGLISH|Exercise Subjective|9 Videos

Similar Questions

Explore conceptually related problems

A plano-convex thin lens of focal length 10 cm is silvered at its plane surface. The distance d at which an object must be kept in order to get its image on itself is

A plano convex lens has focal length f = 20 cm . If its plane surface is silvered, then new focal length will be

A convex lens of focal length 20cm and another plano convex lens of focal length 40cm are placed co-axially . The plano convex lens is silvered on plane surface. What should be the distance (in cm) so that final image of the object 'O' is formed on O itself.

The flat face of a plano-convex lens of focal length 10 cm is silvered. A point source placed 30 cm in front of the curved surface will produce a

For a plane convex lens (mu = 1.5) has radius of curvature 10 cm. It is slivered on its plane surface. Find focal length after silvering:

The redius of curvature of the convex face of a plano-convex lens is 12cm and its refractive index is 1.5. a. Find the focal length of this lens. The plane surface of the lens is now silvered. b. At what distance form the lans will parallel rays incident on the convex face converge? c. Sketch the ray diagram to locate the image, when a point object is places on the axis 20cm from the lens. d. Calculate the image distance when the object is placed as in (c).

A plano-convex lens is made of refractive index of 1.6. The focal length of the lens is

The plane surface of a plano-convex lens of focal length 60 cm is silvered. A point object is placed at a distance 20 cm from the lens. Find the position and nature of the final image formed.

A point object is placed at a distance of 20 cm from a thin plano-concex lens of focal length 15 cm . The plane surface of the lens is now silvered. The image created by the is at :

The plane surface of a plano-convex lens of focal length f is silvered. It will behave as

DC PANDEY ENGLISH-RAY OPTICS-Exercise
  1. The optical density of turpentine is higher than that of water, while ...

    Text Solution

    |

  2. A plano-convex lens is made of refractive index of 1.6. The focal leng...

    Text Solution

    |

  3. A plano-convex lens (f = 20 cm) is silvered at plane surface. The foca...

    Text Solution

    |

  4. A ray of light incident at an angle theta on a refracting face of a pr...

    Text Solution

    |

  5. The distance between an object and a divergent lens is m times the foc...

    Text Solution

    |

  6. A plano-concave lens is made of glass of refractive index 1.5 and the ...

    Text Solution

    |

  7. The figure shows and equiconvex lens of focal length f. It the lens is...

    Text Solution

    |

  8. Assertion A diverging lens (in air) cannot be made more diverging what...

    Text Solution

    |

  9. Assertion A diverging lens (in air) cannot be made more diverging what...

    Text Solution

    |

  10. The optical path of a monochromatic light is same if it goes through 4...

    Text Solution

    |

  11. A ray of light travelling in a transparent medium of refractive index ...

    Text Solution

    |

  12. A ray of light, travelling in a medium of refractive index 'mu, is inc...

    Text Solution

    |

  13. What should be the angle between two plane mirrorrs so that whatever b...

    Text Solution

    |

  14. How much water should be filled in a container of height 21 cm, so tha...

    Text Solution

    |

  15. When a plane mirror is placed horizontally on level ground at a distan...

    Text Solution

    |

  16. A glass prism has refractive index sqrt(2) and refracting angle 30^(@...

    Text Solution

    |

  17. Two thin lenses have a combined power of +9D.When they are separated b...

    Text Solution

    |

  18. Correct exposure for a photographic print is 10 s at a distance of one...

    Text Solution

    |

  19. rays of light strike a horizontal plane mirror at an angle of 45^(@). ...

    Text Solution

    |

  20. A convex lens of focal length 1.0m and a concave lens of focal length ...

    Text Solution

    |