Question

How many alpha and beta particles are emitted when uranium `._(92)^(238)U` decays to lead `._(82)^(206)Pb` ?
A. 6 and B
B. 8 and 6
C. 12 and 6
D. 8 and 12

Answer 1

Correct Answer - B
(B) the number of `alpha ` - particles , `n_(1)`
`=("change in mass number ")/( 4) =(238-206)/(4)implies n_(1) =(32)/(4)=8`
Now , number of `beta `-particles ,`n_(2) =82-(92-2n_(1))`
`=82-(92-2xx8)=82-76=6`