Find the activity of 1 gm of radium `(._(88)Ra^(226))`Whose half life is 1620 years.

Explanation

No. of atoms in 226 gm is `6.023xx10^(23)`
No. of atoms in 1gm `=(6.023xx10^(23))/(226)=2.665xx10^(21)`
Activity 'A' `=lambda N`, 1 year`=365.25xx24xx3600=31.5576xx10^(6)s`
`lambda=(0.693)/(T)` where T=1 year
Activity `=(0.693xx2.665xx10^(21))/(1620xx3.1558xx10^(7))=3.612xx10^(10)`
`A=3.612xx10^(10)` disintegration/sec.