Question

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

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

Answer 1

Answer: (A)

27.9 MeV

Answer 2

The mass defect, $\Delta m=2\left(m_{p}+m_{n}\right)-m_{ He }$
$=2(1.00783+1.00867)-4.00300$
$=0.0300$ amu
So, the binding energy, $E=\Delta m c^{2}$
$=0.03 \times 931 MeV \approx 27.9 \,MeV$