Questions

The Camphor slowly dissolves in the water lowering the latter's surface tension in the immediate neighbourhood. The stronger pull exerted by the uncontaminated portion of water brings about a movement of the surface and the camphor particles are carried along with it. When after sometime the whole surface settles for the reduced tension, the movement of the camphor too short.

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.

According to the Survey, inflation in the country continued to moderate during 2017-18 with the CPI based headline inflation averaging 3.3 per cent during the period --the lowest in the last six financial years

Retail inflation fell to a record low of 2.18% in May as prices of kitchen staples like vegetables and pulses declined sharply although there was a marginal spike in fruit rates.