The half-life of ^226Ra is 1602 y.Calculate the activity of 0.1g of RaCl_2 in which all the radium is in the form of ^226Ra.Taken atomic weight of Ra to be the 226 g mol^-1 and that of C1 to be 35.5 g mol^-1.

Answer

A, B, C, D

Explanation

Given `t_(1/2) = 1602 years`
`Ra = 226 g//mole`
`Ci = 35.5 g//mole`
` 1 mole Ra Cl_2 = 226 + 71 = 297g`
297 g = 1 mole of RaCl_2`
`0.1g = 1/(297) xx 0.1 moleof RaCl_2`
` = (0.1 xx 6.023 xx 10^(23))/(297)`
`= 0.02027 xx 10^(22)`
`lambda = (0.693/t_(1/2))`
` = (0.693)/(1602 xx 365xx 24 xx 3600)`
` = 1.371 xx 10^(-11) xx 2.07 xx 10^(20)`
`= 2.779 xx 10^(9)`
`= 2.8 xx 10^(9) disins.//sec` .