The Neutral Helium Atom ${ } _ { 2 } ^ { 4 }$

Multiple Choice

The neutral helium atom, ${ } _ { 2 } ^ { 4 }$ He, has a mass of $4.002603 \mathrm { u }$ , a neutron has a mass of $1.008665 \mathrm { u }$ , a proton has a mass of $1.007277 \mathrm { u }$ , and a neutral hydrogen atom has a mass of $1.007825 \mathrm { u }$ . What is the binding energy of the ${ } _ { 2 } ^ { 4 } \mathrm { He }$ nucleus? $\left( 1 \mathrm { u } = 931.5 \mathrm { MeV } / c ^ { 2 } \right)$

A) $27.3 \mathrm { MeV }$
B) $20.5 \mathrm { MeV }$
C) $28.3 \mathrm { MeV }$
D) $23.4 \mathrm { MeV }$
E) $22.4 \mathrm { MeV }$