State where an object must be placed so that the image formed by a concave mirror is:
$(a)$ Erect and virtual.
$(b)$ At infinity.
$(c)$ The same size as the object.

Study the given ray diagrams and select the correct statement from the following:
$(A)$ Device $X$ is a concave mirror and device $Y$ is a convex lens, whose focal lengths are $20 \text{ cm}$ and $25 \text{ cm}$ respectively.
$(B)$ Device $X$ is a convex lens and device $Y$ is a concave mirror, whose focal lengths are $10 \text{ cm}$ and $25 \text{ cm}$ respectively.
$(C)$ Device $X$ is a concave lens and device $Y$ is a convex mirror, whose focal lengths are $20 \text{ cm}$ and $25 \text{ cm}$ respectively.
$(D)$ Device $X$ is a convex lens and device $Y$ is a concave mirror, whose focal lengths are $20 \text{ cm}$ and $25 \text{ cm}$ respectively.

An object is placed $15 \text{ cm}$ from $(a)$ a converging mirror, and $(b)$ a diverging mirror, each having a radius of curvature of $20 \text{ cm}$. Calculate the image position and magnification in each case.

Two big mirrors $A$ and $B$ are fitted side by side on a wall. A man is standing at such a distance from the wall that he can see the erect image of his face in both the mirrors. When the man starts walking towards the mirrors, he finds that the size of his face in mirror $A$ goes on increasing, but that in mirror $B$ remains the same.

The image formed by a spherical mirror is virtual. The mirror will be:

No matter how far you stand from a mirror,your image appears erect. The mirror is likely to be