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#### Question

At what distance from a concave lens of focal length 20 cm, should a 6 cm tall object be placed so that it forms an image at 15 cm from the lens ? Also determine the size of the image formed.

#### Solution

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#### Similar questions VIEW ALL

A converging lens has focal length of 12 cm. Calculate at what distance the object should be placed from the lens so that it forms an image at 48 cm on the other side of the lens.

A student has obtained a point image of a distant object using the given convex lens. To find the focal length of the lens he should measure the distance between the :

(A) lens and the object only

(B) lens and the screen only

(C) object and the image only

(D) lens and the object and also between the object and the image

A student was asked by his teacher to find the image distance for various object distance in case of a given convex lens. He performed the experiment with all precautions and noted down his observations in the following table:

S. No. | Object distance (cm) | Image distance (cm) |

1 | 60 | 15 |

2 | 48 | 16 |

3 | 36 | 21 |

4 | 24 | 24 |

5 | 18 | 36 |

6 | 16 | 48 |

After checking the observations table the teacher pointed out that there is a mistake in recording the image distance in one of the observations. Find the serial number of the observations having faulty image distance.

(A) 2

(B) 3

(C) 5

(D) 6

An object of height 4 cm is placed at a distance of 20 cm from a concave lens of focal length 10 cm. Use lens formula to determine the position of the image formed.

What is the magnification of the images formed by plane mirrors and why?