(a) The focal length of the convex mirror is 2.5 m
The customer is 20 m away from the mirror, u = -20 m (as per sign convention)
Using lens formula
Show the image will be formed at a distance of 20/9 m.; the image will be diminished, virtual and erect.
(b) Concave mirrors are used as they converge the reflecting light at the focus. Also the object kept at a distance less than the focal length of the mirror produces enlarged, erect and virtual images of the object; which enables the doctor to clearly see the image of the tooth or the part of the mouth that is being inspected.
(i) Convex lens is used by the palmist to get an enlarged image of the palm revealing the details even more clearly for him when placed real close to the object.
(ii) There are two cases for which a real and magnified image of object is obtained in convex lens-
a. When the object is placed at the focus of the lens.
b. When the object is placed between F and 2F of the lens.
(iii) f= 10
u = - 5
By lens formula
v = -10 cm
The size of the image will be,
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