Question

10. Calculate the number of images formed by two plane mirrors inclined at an angle of:
a) 50° b) 120° c) 72° and d) 40°
11. Why does the image formed by multiple reflections in mirrors placed parallel to each other
become progressively fainter?
12. Why is a convex mirror preffered as a rear-view mirror in automobiles?
13. Draw a suitable diagram to illustrate the action of a :
a) concave mirror and b) convex mirror on a beam of light incident parallel to the principal axis.
14. Name the kind of a mirror used to obtain:
a) a real and enlarged image
b) a virtual and diminished image
c) a virtual and enlarged image
d) a real and diminished image
15. A man standing in front of a special mirror finds his image having a very small head, a fat/enlarged
body and legs of normal size. What are the shapes of the three parts of the mirror?
16. Draw a ray diagram to show the image formation of images when the object is placed in front of a
concave mirror:
a) between its pole and focus
b) beyond centre of curvature

Answer 1

Explanation:

10). b).120°

11). One observes that as the angle between the mirrors decreases, the number of images that can be seen increases. In fact as the angle between the mirrors approaches 0 degrees (i.e., the mirrors are parallel to each other), the number of images approaches infinity.

12).Convex mirrors are used as rear-view mirrors in motor vehicles because they form virtual, erect and diminished images irrespective of distances of the object. Convex mirror helps the driver to view large areas of the traffic behind him and he can easily detect the vehicle coming or running behind him.

13). see in the attachment

14).c) a virtual and enlarged image

15). A man standing extremely close in front of a special mirror finds his image having a very small head, a fat body but legs of similar size. Hence, (a) the top part of the mirror is convex, as it forms virtual, erect and small-sized image.

16). see in the attachment..