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प्रश्न
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उत्तर
The image of an object placed at a long distance in front of a convex mirror is formed at principal focus. The radius of the curvature of convex mirror is 20 cm.
The focal length of the convex mirror = radius of curvature/2.
Focal length of convex mirror = 20/2 = 10 cm.
So the image will form at a principal focus 10 cm away from the pole.
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संबंधित प्रश्न
One half of a convex lens of focal length 10 cm is covered with a black paper. Can such a lens produce an image of a complete object placed at a distance of 30 cm from the lens? Draw a ray diagram to justify your answer. A 4 cm tall object is placed perpendicular to its principal axis of a convex lens of focal length 20 cm. The distance of the object from the lens is 15 cm. Find the nature, position and the size of the image.
A student obtained a sharp image of a burning candle, placed at the farther end of a laboratory table, on a screen using a concave mirror. For getting better value of focal length of the mirror, the subject teacher suggested him for focusing a well illuminated distant object. What should the student do?
(A) He should move the mirror away from the screen.
(B) He should move the mirror slightly towards the screen.
(C) He should move the mirror as well as the screen towards the newly selected object.
(D) He should move only the screen towards the newly selected object.
Draw a ray diagram in each of the following cases to show the formation of image, when the object is placed :
(i) between the optical centre and principal focus of a convex lens.
(ii) anywhere in front of a concave lens.
(iii) at 2F of a convex lens.
State the signs and values of magnifications in the above-mentioned cases (i) and (ii).
What do you understand by the term real image?
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A shopkeeper wanted to fix a mirror which will give a maximum view of his shop. What type of mirror should he use? Give reason.
A ray of light is incident towards a plane mirror at an angle of 30° with the mirror surface. What will be the angle of reflection?
