In the case of a convex mirror,if the object is moved away from the surface of the mirror,how do the position and size of the image change?

$A$ diminished virtual image can be obtained only in

$A$ ray of light is incident normally on a reflecting surface. What are the $(i)$ angle of incidence and $(ii)$ angle of reflection?

If a light ray $IM$ is incident on the surface $AB$ of a rectangular glass slab as shown,identify the correct emergent ray.

$(a)$ State the relation between object distance,image distance and the focal length of a spherical mirror.
$(b)$ Draw a ray diagram to show the image formed by a concave mirror when an object is placed between the pole and focus of the mirror.
$(c)$ $A$ concave mirror of focal length $15\, cm$ forms an image of an object kept at a distance of $10\, cm$ from the mirror. Find the position,nature and size of the image formed by it.

$A$ convex lens has a focal length of $25\, cm$. Calculate the distance of the object from the lens if the image is to be formed on the opposite side of the lens at a distance of $75\, cm$ from the lens. What will be the nature of the image?