$A$ spherical mirror forms an erect image three times the linear size of the object. If the distance between the object and the image is $80 \, cm$,the focal length of the mirror is........$cm$.

$A$ square wire frame of side length $3.0 \, cm$ is placed $25 \, cm$ away from a concave mirror of focal length $10 \, cm$. The center of the wire frame is on the axis of the mirror,with two of its sides perpendicular to the axis. The area of the image will be $..... \, cm^2$.

$A$ person sees his virtual image by holding a mirror very close to the face. When he moves the mirror away from his face,the image becomes inverted. What type of mirror is he using?

Suppose while sitting in a parked car,you notice a jogger approaching towards you in the side view mirror of radius of curvature $R = 2 \; m$. If the jogger is running at a speed of $5 \; m s^{-1}$,how fast does the image of the jogger appear to move when the jogger is $(a) \; 39 \; m$,$(b) \; 29 \; m$,$(c) \; 19 \; m$,and $(d) \; 9 \; m$ away?

$A$ convex mirror is used to form the image of an object. Then which of the following statements is wrong?

The ratio of the diameter of the sun to the distance between the earth and the sun is approximately $0.009$. The approximate diameter of the image of the sun formed by a concave spherical mirror of radius of curvature $0.4 \ m$ is