Question

The radionuclide `.^(238)U` decays by emitting an alpha particle. `.^(238)Uto.^(234)Th+.^(4)He` The atomic masses of the three isotopes are `.^(238)" "U 238.05079 am u`
`.^(234) U" "234.040363 am u`
`.^(4) He " " 4.00260 am u` What is the maximum kinetic energy of the emitted alpha particle. Express your answer in Joule. (`1am u = 1.67 xx 10^(-27)kg`)
A. `6.8xx10^(-14) J`
B. `6.8xx10^(-13) J`
C. `4.3xx10^(-14) J`
D. `4.3xx10^(-13) J`

Answer 1

Mass defect =(238.05079-234.04363-4.00260) u=`4.56 xx10^(-3) u`
`mc^(2) =7.57xx10^(-30)xx9xx10^(16)=6.8xx10^(-13) J`