The common used gas in our refrigerator is

A magnet of pole strength m is divide into four equal parts so that the length as well as the breadth of each part is half of the original magnet. Then pole strength of each part is

Skating on ice is possible because of phenomenon of

Specific resistance of a wire

The half-life of Radium is 1600 years. The fraction of a sample of radium that would remain after 6400 years is

Plants are made disease resistant with