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Question
Which of the following are concave mirrors and which convex mirrors?
Solution
Convex mirror is used as a driving mirror, staircase mirror in a double-decker bus and shop security mirror.
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RELATED QUESTIONS
Draw a ray diagram to show the path of the refracted ray in each of the following cases:-
A ray of light incident on a concave lens is
(i) passing through its optical centre.
(ii) parallel to its principal axis.
(iii) directed towards its principal focus.
Find the focal length of a concave mirror whose radius of curvature is 32 cm.
Draw diagram to represent the action of a concave mirror on a beam of parallel light rays. Mark on this diagram principal axis, focus F, centre of curvature C, pole P and focal length f, of the concave mirror.
According to the "New Cartesian Singh Convention" for mirrors, what sign has been given to the focal length of:
a convex mirror?
An object is placed at a distance of 10 cm from a concave mirror of focal length 20 cm.
State two characteristics of the image formed.
A real image of an object is to be obtained. The mirror required for this purpose is:
(a) convex
(b) concave
(c) plane
(d) either convex or concave
List four characteristics of the image formed by a concave mirror of focal length 40 cm when the object is placed in front of it at a distance of 20 cm from its pole.
Give any two applications of a concave and convex mirror.
A concave mirror of radius 30 cm is placed in water. It’s focal length in air and water differ by ______.
A student took three concave mirrors of different focal lengths and performed the experiment to see the image formation by placing an object at different distance with these mirrors as shown in the following table.
| Case No. | Object-distance | Focal length |
| I | 45 cm | 20 cm |
| II | 30 cm | 15 cm |
| III | 20 cm | 30 cm |
Now answer the following questions:
(a) List two properties of the image formed in Case I.
(b) In which one of the cases given in the table, the mirror will form real image of same size and why?
(c) Name the type of mirror used by dentists. Given reason why do they use such type of mirrors.
OR
(c) Look at the table and identify the situation (object distance and focal length) which resembles the situation in which concave mirrors are used as shaving mirrors? Draw a ray diagram to show the image formation in this case.
