$A$ convex mirror of focal length $f$ forms an image which is $\frac{1}{n}$ times the size of the object. The distance of the object from the mirror is

The cross-section of a reflecting surface is represented by the equation $x^{2}+y^{2}=R^{2}$ as shown in the figure. $A$ ray travelling in the positive $x$ direction is directed toward the positive $y$ direction after reflection from the surface at point $M$. The coordinate of the point $M$ on the reflecting surface is

Two objects $A$ and $B$ are placed at $15\,cm$ and $25\,cm$ from the pole in front of a concave mirror having a radius of curvature $40\,cm$. The distance between the images formed by the mirror is $..........\,cm$.

The field of view is maximum for

The convergence of a concave mirror can be decreased by dipping it in which of the following?

$A$ concave mirror has a focal length $20\,cm$. The distance between the two positions of the object for which the image size is double of the object size is......$cm$