The maximum magnification that can be obtained with a convex lens of focal length $2.5\ cm$ is ( the least distance of distinct vision is $25\ cm$)

The distance between the extreme points on the periphery of the mirror is called:

Which lens has magnification less than $1 ?$

A plane mirror produces an image that is

উত্তল দর্পণের  সামনে বস্তু রাখলে প্রতিবিম্ব সর্বদা-