Questions

Sceptic means doubterCryptic means mysteriousBeliever means who believes in the truthwhich is nearly opposite in meaning to ScepticEminent means prestigious

A periscope is an optical instrument that uses a system of prisms, lenses, or mirrors to reflect images through a tube.

Light from a distant object strikes the top mirror and is then reflected at an angle of 90 degrees down the periscope tube. At the bottom of the periscope, the light strikes another mirror and is then reflected into the viewer’s eye.

Hence, A periscope works by the principle of Total internal reflection.

The transformation of Hydrogen atoms into Helium atoms with an emission of vast amount of energy is called nuclear fusion which is the source of energy for the Sun.