An object placed in front of a concave mirror of focal length $0.15 \,m$ produces a virtual image,which is twice the size of the object. The position of the object with respect to the mirror is ........... $cm$. (in $.5$)

An object ' $O$ ' is placed at a distance of $100\,cm$ in front of a concave mirror of radius of curvature $200\,cm$ as shown in the figure. The object starts moving towards the mirror at a speed of $2\,cm/s$. The position of the image from the mirror after $10\,s$ will be at ...... $cm$.

$A$ spherical mirror forms an erect image of an object,three times the size of the object. If the distance between the object and the image is $80 \ cm$,then the focal length of the mirror is ......... $cm$.

$A$ convex mirror has a radius of curvature of $22 \; cm$. If an object is placed $14 \; cm$ away from the mirror,then its image is formed at:

The distance between an object and its image (magnified by $-\frac{1}{3}$) is $30 \ cm$. The focal length of the mirror used is $\left(\frac{x}{4}\right) \ cm$,where the magnitude of the value of $x$ is . . . . . . .

Assertion : $A$ point object is placed at a distance of $26 \ cm$ from a convex mirror of focal length $26 \ cm$. The image will not form at infinity.
Reason : For the above-given system,the equation $\frac{1}{v} + \frac{1}{u} = \frac{1}{f}$ gives $v = \infty$.