Answer:
7.45 Mev
Explanation:
in this case we need to considerated the following formula
alpha = E/Eo
where:
alpha = (A - 1)square /(A + 1)square
and A is the mass number of nucleus
, for this case the Ba is 56
so we replace the values
alpha = (56 - 1)square /(56+ 1)square
alpha = 55²/57²
E = 8×55×55/57×57
E = 7.45 Mev
