When a plane mirror is rotated by an angle $\theta$,the reflected ray turns by an angle $2\theta$. Is this statement true or false?

Which type of mirror can produce a virtual image?

Give the relationship of magnification with focal length of a spherical mirror.

$(a)$ Define radius of curvature and focal length of a spherical mirror and show it on a figure.
$(b)$ Write the relation between the radius of curvature and the focal length of a spherical mirror.

An object $1 \, cm$ tall is placed at a distance of $15 \, cm$ from a concave mirror of focal length $10 \, cm$. Find the position,size,and nature of the image formed.

What is the focal length of a convex lens having power $+5.0 \,D$?