Questions

The most number of countries are in the continent Africa. Eventhough, Asia is the biggest continent in its size, Africa is the continent with 54 countries whereas Asia have 48 countries.

Lord Kelvin, working in Scotland, developed the Kelvin scale in 1848. His scale uses molecular energy to define the extremes of hot and cold. Absolute zero, or 0 K, corresponds to the point at which molecular energy is at a minimum. The Kelvin scale is preferred in scientific work, although the Celsius scale is also commonly used. Temperatures measured on the Kelvin scale are reported simply as K, not °K.

T (in °C) + 273.15 = T (in K)

T (in K) − 273.15 = T (in °C)

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.

In S.I. System unit of angular momentum is "joule.Second".

SI unit of Planck's constant is joule-seconds(j-s).

In the given options, BIS is the odd one from the other three.  NABARD, RBI & IRDA are the bodies related to financial sector of India. The financial sector consists of banks, investment funds, insurance companies and real estate firms. 

BIS stands for Beareau of Indian Standards is a National standard body of India with the activities of standardization, marking and quality certification of goods.