$A$ concave mirror of focal length $f$ in air is dipped in a liquid of refractive index $\mu$. Its focal length in the liquid will be $:$

$A$ convex mirror has a radius of curvature of $22 \; cm$. If an object is placed $14 \; cm$ away from the mirror,then its image is formed at:

$A$ concave mirror of radius of curvature $R$ has a circular outline of radius $r$. $A$ circular disc is to be placed normal to the axis at the focus,so that it collects all the light that is reflected from the mirror from a beam parallel to the axis. For $r \ll R$,the area of this disc has to be at least

In the case of spherical mirrors,the images formed on the side of the object and images formed on the opposite side are respectively

For a concave mirror,the $\frac{1}{u}$ versus $\frac{1}{v}$ graph obtained by the parallax method is as shown in the figure. The graph is a straight line with a slope of $-1$. The estimated value of the focal length of the mirror is: (in $cm$)

$A$ man having height $6 \ m$ observes an erect image of height $2 \ m$. The mirror used is: