Question

An alpha particle ${(}^{4}He)$ has a mass $4.00300amu$. A proton has a mass $1.00783$ amu and a neutron has a mass $1.00867amu$ respectively. The binding energy of alpha estimated from these data is closest to:

• A. $27.9MeV$
• B. $22.3MeV$
• C. $35.0MeV$
• D. $20.4MeV$

Answer 1

The correct option is A $27.9MeV$

The mass defect, $\Delta m=2(m_p+m_n)-m_{He}$
$=2(1.00783+1.00867)-4.00300$
$=0.300amu$
So, the binding energy $E=\Delta m{c}^2$$=0.03\times 931MeV=27.9MeV$