Question

A test tube immersed at a certain angle in a tumbler of water to have a mirror surface for a certain
viewing position. What is the reason for this?​

Answer 1

Answer:

The reason for this is:

1.)when rays of light travel through water strikes the water glass interface of test tube at an anglevwhich is more than critical angle for water. then the light ray suffer total internal reflection. 2.)when these totally reflected rays reach the eye , then they appear to come from surface of test tube.

Answer 2

Answer:

1. The surface aur the test tube separates water and air.
2. As light tries to enter air in the test tube(rarer medium),it undergoes total internal reflection bouncing back to water from the surface of the test tube giving it a shiny mirror like surface.