When an object is placed at the center of curvature $(C)$ in front of a concave mirror,what kind of image is formed?

Where should an object be placed to use a convex lens as a simple microscope?

An object is placed at the following distances from a concave mirror of focal length $15 \, cm$.
$(a)$ $10 \, cm$ $(b)$ $20 \, cm$ $(c)$ $30 \, cm$ $(d)$ $40 \, cm$
Which position of the object will produce:
$(1)$ Virtual image
$(2)$ $A$ diminished real image
$(3)$ An enlarged real image
$(4)$ An image of same size

Which of the following is the correct general form of Snell's law?

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

Explain why drivers prefer to use a convex mirror as a rearview mirror in automobiles.