Correct option is B
Given
Focal length of a concave mirror = 2.5 cm
For a dentist's mirror, the image must be upright and magnified → this happens only when the object is placed between the mirror and its focal point.
For a dentist's mirror, the image must be upright and magnified → this happens only when the object is placed between the mirror and its focal point.
Formula used
A concave mirror produces an erect, magnified, virtual image only when:
object distance < focal length
object distance < focal length
Solution
Focal length = 2.5 cm
To get an erect, magnified image of the tooth → the tooth must be closer than 2.5 cm to the mirror.
To get an erect, magnified image of the tooth → the tooth must be closer than 2.5 cm to the mirror.
Among the options, the only distance less than 2.5 cm is:
The correct option is (B) 1.5 cm
English
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