State the laws of reflection.

If you want to see an enlarged image of your face, which type of mirror will you use? Where will you place your face?

The figure shows a ray of light as it travels from medium $A$ to medium $B$. The refractive index of medium $B$ relative to medium $A$ is:

$A$ $10 \, cm$ tall object is placed perpendicular to the principal axis of a convex lens of focal length $30 \, cm$. The distance of the object from the lens is $20 \, cm$. Find the $(i)$ position,$(ii)$ nature,and $(iii)$ size of the image formed.

The image formed by a concave mirror is real and of the same size. Where is the object placed?

$A$ convex lens forms a real and inverted image of a needle at a distance of $50\, cm$ from the lens. Where should the needle be placed in front of the convex lens so that this image is of the same size as the object? Also, find the power of the lens.