Magnification produced by a rear-view mirror fitted in vehicles $....$

How can you distinguish between a plane mirror,a convex mirror,and a concave mirror by merely looking at the image formed in each case?

For a concave mirror,if the object distance $u = \infty$,then the image distance $v = ..........$.

$(a)$ Draw a ray diagram in each of the following cases to show the position and nature of the image formed when the object is placed:
$(i)$ between optical centre and principal focus $(F)$ of a convex lens.
$(ii)$ between $F$ and $2F$ of a convex lens.
$(iii)$ at $2F$ of a convex lens.
$(b)$ How will the nature and position of the image formed change in case $(i)$ and $(ii)$ in part $(a)$ of this question if the lens is replaced by a concave lens? Draw the corresponding ray diagram.

The power of a lens is $2.5$ dioptre. What is the focal length and the type of lens?

$A$ $2.0 \text{ cm}$ tall object is placed perpendicular to the principal axis of a convex lens of focal length $10 \text{ cm}$. The distance of the object from the lens is $15 \text{ cm}$. Find the position,nature,and size of the image formed.