The activity of one gram of radium is equal to _________.

One gram of oxygen is equal to

One gram of fat gives

5,045 grams is equal to:

One gram is more than _________ .

The nature of the oxide of radium is

The nature of the oxide of radium is

The activity of 1 g radium is found to be 0.5. Calculate the half-life period of radium and the time required for the decay of 2 g of radium to give 0.25 g of radium (atomic mass off radium = 226).