Question

The masses of neutron and proton are $1.0087$ and $1.0073$ amu respectively. If the neutrons and protons combine to form a Helium nucleus of mass $4.0015amu$, the binding energy of the Helium nucleus will be :

• A. $28.4MeV$
• B. $20.8MeV$
• C. $27.3MeV$
• D. $14.2MeV$

Answer 1

The correct option is A $28.4MeV$

Mass of neutron $=1.0087amu$

Mass of proton $=1.0073amu$

In a helium nucleus,

protons $=2$

neutrons$=2$

Mass(theoritically) $=(2\times 1.0087+2\times 1.0073)$

$=4.032$

Mass defect $=(4.032-4.0015)amu$

$=0.0305amu$

So, $1amu$ gives $931.5MeV$ of energy.

So, $0.0305\times 931.5MeV$ of binding energy $=28.4MeV$