Write down four important characteristics of the image formed by a plane mirror.

Where should the light source (bulb) be placed in the reflector of a searchlight or torch so that the light rays travel over a long distance?

What can be measured using a dioptre meter?

Which lens can be used as a magnifying glass? For which position of the object does a convex lens form:
$(a)$ a virtual and erect image?
$(b)$ a real and inverted image of the same size as that of the object?
Draw labelled ray diagrams to show the formation of the required image in each of the above two cases.

State the relation between object distance,image distance,and focal length of a concave or convex mirror. $A$ concave mirror produces a two times magnified real image of an object placed at $10 \ cm$ from it. Find the position of the image.

With the help of a ray diagram,show that the angle of incidence is equal to the angle of reflection when a ray is incident on a concave mirror.