On what factor does the lateral shift produced by a glass slab depend?

$A$ convex mirror can be used to see a large image of a small object.

The velocity of light in a vacuum is $....$

$A$ convex mirror is used to form the image of a real object. Then tick the wrong statement.

The figure below shows an object $AB$ placed on the principal axis of a convex lens placed in air. $F_{1}$ and $F_{2}$ are the two foci of the lens. Copy the diagram.
$(i)$ Draw a ray of light starting from $B$ and passing through $O$. Show the same ray after refraction by the lens.
$(ii)$ Draw another ray from $B$ which passes through $F_{2}$ after refraction by the lens.
$(iii)$ Locate the final image formed.
$(iv)$ Is the image real or virtual?

If the radius of curvature of a spherical mirror is $30 \ cm$,what is its focal length (in $cm$)?