Where should an object be placed in front of a convex lens to form a real,inverted,and same size image?

For what position of the object does a convex lens form an erect and virtual image?

$A$ $10\, mm$ long awl pin is placed vertically in front of a concave mirror. $A$ $5\, mm$ long image of the awl pin is formed at $30\, cm$ in front of the mirror. The focal length of this mirror is ......... $cm$.

The following table gives the values of refractive indices of a few media:

$S.No.$	$1$	$2$	$3$	$4$	$5$
Medium	Water	Crown glass	Rock salt	Ruby	Diamond
Refractive index	$1.33$	$1.52$	$1.54$	$1.71$	$2.42$

Use this table to give an example of $(i)$ a medium pair so that light speeds up when it goes from one of these media to another. $(ii)$ a medium pair so that light slows down when it goes from one of these media to another.

Both a spherical mirror and a thin spherical lens have a focal length of $-15 \; cm$. What type of mirror and lens are they?

If an object is placed between two plane mirrors inclined at an angle of $45^{\circ}$,then the number of images formed will be $9$. State whether this statement is True or False.