Draw a ray diagram to show the formation of an image when an object is placed between focus $\left({\mathrm{F}}_1\right)$ and optical centre $\left(\mathrm{O}\right)$ of a convex lens.

A concave mirror produces $3$ times enlarged image of an object placed $10 \mathrm{cm}$ in front of it. Calculate its radius of curvature.

Select the correct alternative from those given below each statement and write the completed statement :

The power of a convex lens is $+4 \mathrm{D}$, then its focal length will be ______.

In a Solar Furnace, sunlight is concentrated at the ________ of the concave mirror.

A ray of light travelling in air enters obliquely into a glass slab. Does the ray move towards the normal or away from it?

Name the law represented by the formula: $n=\frac{\sin \mathrm{i}}{\sin \mathrm{r}}$

Vimal combs her hair is front of a plane mirror. Write two characteristics of her image.

Draw a Ray diagram to show the formation of an image when the object is placed between the pole and the focus of a Concave Mirror.

If the Magnification produced by a Convex Lens is $-1.5$, what would be the position and nature of the image.