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Question
What is the advantage of using a convex mirror as rear-view mirror in vehicles as compared to a plane mirror? Illustrate your answer with the help of labelled diagrams.
Solution
A convex mirror has a wider field of view, and always forms virtual, erect and small-sized images of a large number of objects at the same time. Size of the image formed by a plane mirror is equal to the size of the object; hence, it has a small field of view as compared to the convex mirror. Thus, a convex mirror is used as a rear view mirror in a car.
Following ray diagram explains it all:
RELATED QUESTIONS
No matter how far you stand from a mirror, your image appears erect. The mirror is likely to be ______.
Draw diagram to show the action of convex 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 convex mirror.
If the focal length of a spherical mirror is 12.5 cm, its radius of curvature will be:
(a) 25 cm
(b) 15 cm
(c) 20 cm
(d) 35 cm
If you want to see an enlarged image of your face, state whether you will use a concave mirror or a convex mirror?
An object is placed at a distance of 10 cm from a convex mirror of focal length 5 cm.
(a) Draw a ray-diagram showing the formation image
(b) State two characteristics of the image formed
(c) Calculate the distance of the image from mirror.
A shop security mirror 5.0 m from certain items displayed in the shop produces on-tenth magnification.
What is the type of mirror?
An object is placed at the following distance from a convex lens of focal length 15 cm:
(a) 35 cm
(b) 30 cm
(c) 20 cm
(d) 10 cm
Which position of the object will produce:
(i) a magnified real image?
(ii) a magnified virtual image?
(iii) a diminished real image?
(iv) an image of same size as the object?
To determine the focal length of a convex lens by obtaining a sharp image of a distant object we generally follow the following steps which are not in proper sequence.
(a) Hold the lens between the object and the screen
(B) Measure the distance between the lens and the screen
(C) Select a well lit distant object
(D) Place a screen opposite to the object on the lab table
(e) Adjust the position of the lens to form a sharp image
The correct sequence of these steps is:
(A) c, a, d, e, b
(B) c, d, a, e, b
(C) c, d, e, a, b
(D) c, a, e, d, b
When the reflecting surface is curved outwards the mirror formed will be ______.
Match the following.
| Column I | Column II |
| Convex mirror | Radio telescopes |
| Parabolic mirror | Rear-view mirror |
| Snell’s law | Kaleidoscope |
| Dispersion of light | sin i/sin r =μ |
| Refractive index | Rainbow |
