Explain briefly the following day to day events:
(a) A swimming pool appears shallower than what it actually is.
(b) A convex lens can be used as a magnifier, but a concave lens cannot be.
( c) A convex mirror is used as a rear view mirror by the drivers of motor vehicles.
(d) A concave mirror is used by ENT specialists.
(e) A convex mirror is used as a refleactor in street lamps.

Explanation

(a) It happens on account of refraction of light. The rays starting from the bottom of the tank bend away from normal at the surface of water. That is why bottom of the tank appears raised.
(b) When an object is held between optical centre and principal focus of a convex lens, it forms a virtual, erect and magnified image. That is why a convex lens acts as a magnifier. But for any position of the object, image formed by a concave lens is virtual, erect and shorter. Therefore, a concave lens cannot act as magnifier.
(c ) This is because image formed by a convex mirror is always virtual, erect and smaller in size. The mirror has a large field of view.
(d) This is because a concave mirror can concentrate a parallel beam of light onto a particular part of the body to be examined.
(e) A convex mirror is used as a reflector in street lamps because it would diverge the rays of light falling on it from the source.