Concepts Of Physics MCQ Edition [Volume 2]PhysicsThe Nucleus
Determine the mass of an -particle, given that its binding energy is 28.2 MeV .
Options
- A4.0319 u
- B4.0622 u
- C4.0016 u
- D3.9713 u
Correct answer
C. 4.0016 u
Step-by-step solution
The -particle is a helium nucleus, which consists of 2 protons and 2 neutrons. Mass of a proton, m_p 1.00727 u Mass of a neutron, m_n 1.00866 u The total mass of the constituent nucleons is: M_ nucleons = 2m_p + 2m_n M_ nucleons = 2(1.00727 u ) + 2(1.00866 u ) M_ nucleons = 2.01454 u + 2.01732 u = 4.03186 u The mass defect m is related to the binding energy (BE) by the relation: m = BE 931.5 MeV/u m = 28.2 MeV 931.5 MeV/u 0.03027 u The mass of the -particle is the total mass of the nucleons minus the mass defect: M