Question

The focal length of a small concave mirror is 2.5 cm. In the distance of tooth from the mirror should be : (a) 2.5 cm (b) 1.5 cm (c) 4.5 cm (d) 3.5 cm

Answer 1

Answer : (b)1.5 cm

Explanation :
The tooth wants to be magnified for seeing clearly.To form magnified image of the tooth by a concave mirror the object i.e tooth must be placed within the focus. Therefore the distance of tooth from the mirror should be less than the focal length (lessthan 2.5cm). So, in the given option the correct value is 1.5 cm.