Home
Class 12
PHYSICS
A biconvex lens is cut in such a way tha...

A biconvex lens is cut in such a way that its equal two halves are (i) XOX. and (ii) YOY.axis respectively. If the focal length of original lens is fi f. is focal length in case (i) and fi in case (ii), then which of the following is true ?

A

f.=2f,f..=2f

B

f.=f,f..=2f

C

f.=2f,f..=f

D

f.=f,f..=f

Text Solution

Verified by Experts

The correct Answer is:
B

`1/f=(mu-1)((1)/(R_1)-(1)/(R_2))` In this case, `R_1` and `R_2` doesn.t change. Hence, focal length of both is f.
`therefore f.=f`

which is combination of two lenses of same focal length.
`therefore 1/f=(1)/(f_1)+(1)/(f_2)` where `f_1=f_2=f..`
`therefore 1/f=(1)/(f..)+(1)/(f..)=(2)/(f..)`
`thereforef..=2f`
Promotional Banner

Topper's Solved these Questions

  • RAY OPTICS AND OPTICAL INSTRUMENTS

    KUMAR PRAKASHAN|Exercise SECTION-D (MULTIPLE CHOICE QUESTIONS (MCQs))(MCQs FROM .DARPAN. BASED ON TEXTBOOK)(MCQs BASED ON TEXTUAL ILLUSTRATION AND EXERCISE)|24 Videos

  • MOVING CHARGES AND MAGNETISM

    KUMAR PRAKASHAN|Exercise SECTION D (MCQs ASKED IN COMPETITIVE EXAMS)|34 Videos

  • SAMPLE QUESTION PAPER

    KUMAR PRAKASHAN|Exercise PART-B SECTION-C|5 Videos

Similar Questions

Explore conceptually related problems

If the focal length of a lens for red and violet light rays respectively are f_R and f_V then which of the following is true relationship ?

Focal length of convex lens for red, green and blue colour are f_r , f_g , and f_b respectively, so which of the following statements is true ?

A biconvex lens of focal length f forms a circular image of radius r of sun in focal plane . Then which option is correct

For a thin convex lens when the heights of the object is double than its image, its object distance is equal to ....... Focal length of a lens is f.

Calculate equivalent focal length of plano convex lens for following case:- (i) When curved surface is silvered. (ii) When plane surface is silvered.

A convex lens has a focal length f. It is cut inti two parts along the dotted lines as shown ii figure. The focal length of each part will be …....... .

(i) If f = 0.5 m for a glass lens, what is the power of the lens? (ii) The radii of curvature of the faces of a double convex lens are 10 cm and 15 cm. Its focal length is 12 cm. What is the refractive index of glass? (iii) A convex lens has 20 cm focal length in air. What is focal length in water? (Refractive index of air-water = 1.33, refractive index for air-glass = 1.5.)

The focal length of an equiconvex lens in air i equal to either of its radii of curvature. The refractive index of the material of the lens is …........

(i) If f = + 0.5 m , what is the power of the lens ? (ii) The radii of curvature of the faces of a double convex lens are 9 cm and 15 cm . Its focal length is 12 cm . What is the refractive index of glass ?

Four combinations of two thin lenses are given in List I . The radius of curvature of all curved surfaces is r and the refractive index of all the lenses is 1.5 Match lens combinations in List I with their focal length in List II and select the correct answer using the code given below the lists. (A) (p) 2 r (B) (q) ( r)/(2) ( C) (r) - r (D) (s) r . Code :

KUMAR PRAKASHAN-RAY OPTICS AND OPTICAL INSTRUMENTS-SECTION-D (MULTIPLE CHOICE QUESTIONS (MCQs))(MCQs ASKED IN COMPETITIVE EXAMS)
  1. An object is there on a wall. Now by help of convex lens, an image of ...

    Text Solution

    |

  2. As shown in figure, a ray of light is incident on glass cube. If it ex...

    Text Solution

    |

  3. A biconvex lens is cut in such a way that its equal two halves are (i)...

    Text Solution

    |

  4. A mixed ray of red and green colour incidents obilquely on surface of ...

    Text Solution

    |

  5. Diameter of objective of a telescope is 10 cm Its distance from two di...

    Text Solution

    |

  6. Angular resolution of telescope is of order of ...... for 10 cm object...

    Text Solution

    |

  7. A combination is formed by keeping a convex lens in contact with a con...

    Text Solution

    |

  8. A microscope is arranged to observe a mark on a piece of paper clearly...

    Text Solution

    |

  9. Frequency and wavelength of light in transparent material are 2xx10^(1...

    Text Solution

    |

  10. A coin is at rest at bottom of a tank filled with liquid. A ray of lig...

    Text Solution

    |

  11. A boy focuses Sunlight on a paper by using biconvex lens of focal leng...

    Text Solution

    |

  12. A ray of light travels in medium of refractive index mu. It incidents ...

    Text Solution

    |

  13. Which of the following phenomenon doesn.t depend on total internal ref...

    Text Solution

    |

  14. Radius of curvature of a biconvex lens is 20 cm. An object of 2 cm hei...

    Text Solution

    |

  15. A prism of refractive index mu = 1.5 and prisim angle 15^@ is arranged...

    Text Solution

    |

  16. A converging light beam incidents on diverging lens. After passing thr...

    Text Solution

    |

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

    Text Solution

    |

  18. The angle of a prism is A. One of its refracting surfaces is silvered....

    Text Solution

    |

  19. Two identical thin plano-convex glass lenses (refractive index 1.5) ea...

    Text Solution

    |

  20. The refracting angle of a prism is A and refrac tive index of the mate...

    Text Solution

    |