In an experiment to find the focal length of a concave mirror,a graph is drawn between the magnitudes of $u$ and $v$. The graph looks like:

An object is placed on the principal axis of a concave mirror at a distance of $1.5 f$ ($f$ is the focal length). The image will be at ....... $f$.

An object of length $f/3$ is placed on the principal axis of a concave mirror of focal length $f$. The image of the end of the object farthest from the mirror is formed at the same position. Find the length of the image.

In the parallax method for the determination of the focal length of a concave mirror, the object should always be placed:

$A$ short linear object $O$ is placed on the principal axis of a convex mirror of focal length $f$ as shown in the figure. The ratio of transverse magnification to longitudinal magnification is

$A$ point object is between the Pole and Focus of a concave mirror,and moving away from the mirror with a constant speed. Then,the velocity of the image is: