Give two examples of transparent medium that are denser than air.

In the following questions, the statement of assertion is followed by a reason. Mark the correct choice as:

Assertion: For observing the traffic at a hairpin bend in mountain paths a plane mirror is preferred over convex mirror and concave mirror.

Reason: A convex mirror has a much larger field of view than a plane mirror or a concave mirror.

In the following questions, the statement of assertion is followed by a reason. Mark the correct choice as:

Assertion: Incident ray is directed towards the centre of curvature of spherical mirror. After reflection it retraces its path.

Reason: Angle of incidence i = Angle of reflection r = 0^o.

According to cartesion sign convention, which mirror and which lens has negative focal length?

A coin in a glass beaker appears to rise as the beaker is slowly filled with water, why?