The focal length of a concave mirror is $50 \, cm$. Where should an object be placed so that its image is two times magnified and inverted?

$A$ rod of length $10 \text{ cm}$ lies along the principal axis of a concave mirror of focal length $10 \text{ cm}$ as shown in the figure. The length of the image is . . . . . . $\text{cm}$.

$A$ diminished virtual image can be formed only in

The image formed by a convex mirror of focal length $f$ is $(1/n)$ times the size of the object. The distance of the object from the mirror is:

$A$ concave mirror of focal length $10$ cm forms an image which is double the size of the object when the object is placed at two different positions. The distance between the two positions of the object is . . . . . . cm.

An object is placed at $20 \, cm$ from a convex mirror of focal length $10 \, cm$. The image formed by the mirror is