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प्रश्न
In sunglasses, both of its surfaces are curved, yet their behaviour is neither like a convex lens nor like a concave lens. State the reason.
उत्तर
In sunglasses, the outer surface is convex and the inner surface is concave, hence the power of one surface is positive and that of the other is negative. By making both these powers equal, the effective power of the lens becomes zero. Hence, these lenses are simply like a thin glass having no power, plus or minus.
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संबंधित प्रश्न
A student wants to project the image of a candle flame on the walls of school laboratory by using a lens:-
(a) Which type of lens should be use and why?
(b) At what distance in terms of focal length 'F' of the lens should be place the candle flame so as to get (i) a magnified, and (ii) a diminished image respectively on the wall?
(c) Draw ray diagram to show the formation of the image in each case?
When a ray of light enters from one medium to another having different optical densities it bends. Why does this phenomenon occur?
For what position of an object a real, diminished image is formed by a convex lens?
Explain with the help of a diagram, why the convex lens is also called a converging lens.
Find the nature, position and magnification of the images formed by a convex lens of focal length 0.20 m if the object is placed at a distance of:
0.25 m
When you focus the image of a distant flag, whose shape is given below, on a screen using a convex lens, the shape of the image as it appears on the screen is
(A)
(B)
(C)
(D)
A teacher sets up the stand carrying a convex lens of focal length 15 cm at 42.7 cm mark on the optical bench. He asks four students A, B, C and D to suggest the position of screen on the optical bench so that a distinct image of a distant tree is obtained almost immediately on it. The positions suggested by the students were as
A. 12.7 cm
B. 29.7 cm
C. 57.7 cm
D. 72.7 cm
The correct position of the screen was suggested by
(a) A
(b) B
(c) C
(d) D
Out of the two lenses one concave and the other convex state which is a convergent or a divergent type of a lens. Give a reason for your answer.
Simple microscope : Number of convex lens one : : compound microscope : _______
Which of the following statements is true?
