Question

Which of the following transmutations demonstrate(s) beta decay?
i. $Bu-212\to Po-212$
ii. $Pb-212\to Bi-212$
iii. $Ra-228\to Ac-228$

• A. i only
• B. ii only
• C. ii and iii only
• D. i and ii only
• E. i, ii and iii

Answer 1

The correct option is E i, ii and iii

All the given transmutations demonstrates beta decay.
In beta decay, the atomic number increases by 1 and the mass number remains same. This is because, a beta particle is an electron with charge -1 and mass 0.
${}_{83}^{212}Bi{\to }_{84}^{212}Pu{+}_{-1}^0\beta$
${}_{82}^{212}Pb{\to }_{83}^{212}Bi{+}_{-1}^0\beta$
${}_{88}^{228}Ra{\to }_{89}^{228}Ac{+}_{-1}^0\beta$