Cathode ray is a beam of electrons emitted   from   the   cathode   of   a vacuum    tube.    It    is    invisible. Cathode  ray  tubes  are  also  found in     televisions     and     computer monitors.  Since  cathode  ray  is  a beam of electrons and all electrons are  identical,  charge  to  mass  ratio is same for all the gases and does not depend on the nature of gas.

Chemical  properties of  an element depend   on the number   and   the configuration   of   their   (valence) electrons.

There   are five known   states   of matter:    solids,    liquids,    gases, plasma and Bose-Einstein condensates.  The  main  difference in the structures of each state is in the densities of the particles.

All  are  correct  except  B  as  Aridisol is just like sand like soil as in Arid region  e.g.  In  Rajasthan,  so  there will be very less amount of organic matter.

All   are   correct   except   4   as   a cloudburst  can  occur  anytime  and at  any  place  which  is  affected  by convective weather system.

All   are   correct   except   D,   as Tsunami is a Japanese word

Tropical rainforests are such rainforests that occur in the region of tropical rainforest climate where there is no dry season and it remain hot and wet.Tropical evergreen rainforest biome provides optimum environmental conditions for the growth of plants and animals because it experience heavy rainfall and high temperature, and extend between 10° N and 10° S latitudes. The biome Tropical rain forests are of mega thermal type because the organisms are adapted to high temperature and wet and humid condition. The maximum development of this biome has taken place in South America, lowland regions in Africa, and the islands off of Southeast Asia, Central America and parts of Australia.

On December 21, the earth is in an equivalent position on the opposite points in its orbit, So the South pole is tipped towards the sun and North pole away from it resulting in 24 hours of darkness at the North pole, as the sun is overhead on the Tropic of Capricorn. This phenomenon is winter solstice; while on June 21, North pole is tipped towards the Sun but the South pole is tipped away from the sun resulting in 24 hours of darkness on the South Pole, as the sun is overhead on the Tropic of Cancer.This phenomenon is summer solstice; while Aphelion is the position of the earth in its orbit when it is at its distant point from the sun.