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प्रश्न
A convex lens produces a magnification of + 5. The object is placed:
(a) at focus
(b) between f and 2f
(c) at less than f
(d) beyond 2f
उत्तर
At less than f
since the magnification is positive, the image formed is virtual, erect and enlarged. This is the case when an object is placed at a distance of less than f of the lens.
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संबंधित प्रश्न
An object of 10 cm is placed in front of a plane mirror. The height of image will be …………….
(a) 5 cm
(b) 15 cm
(c) 20 cm
(d) 10 cm
Give two circumstances in which a concave mirror can form a magnified image of an object placed in front of it. Illustrate your answer by drawing labelled ray diagrams for both.
Which one of these circumstances enables a concave mirror to be used as a shaving mirror?
A virtual, erect and magnified image of an object is to be produced with a concave mirror of focal length 12 cm. Which of the following object distance should be chosen for this purpose?
(i) 10 cm
(ii) 15 cm
(iii) 20 cm
Give reason for your choi
At what distance from a converging lens of focal length 12 cm must an object be placed in order that an image of magnification 1 will be produced?
Determine how far an object must be placed in front of a converging lens of focal length 10 cm in order to produce an erect (upright) image of linear magnification 4.
If a magnification of, –1 (minus 1) is obtained by using a converging lens, then the object has to be placed:
(a) within f
(b) at 2f
(c) beyond 2f
(d) at infinity
An object is 0.09 m from a magnifying lens and the image is formed 36 cm from the lens. The magnification produced is:
(a) 0.4
(b) 1.4
(c) 4.0
(d) 4.5
The magnification produced by a spherical lens and a spherical mirror is + 2.0.
(a) The lens and mirror are both concave
(b) The lens and mirror are both convex
(c) The lens is convex but the mirror is concave
(d) The lens is concave but the mirror is convex
The power of a lens is +4D. Find the focal length of this lens. An object is placed at a distance of 50 cm from the optical centre of this lens. State the nature and magnification of the image formed by the lens and also draw a ray diagram to justify your answer.
