Calculate the mass defect of the helium nucleus 42He. The mass of neutral 42He is given by MHe=4.002603u.

We have the following values used to solve this:

For ⁴₂He:

No of protons: 2

No of neutrons : 2

Mass of proton: 1.00728 amu

Mass of neutron: 1.00867 amu

Atomic mass: 4.002603 amu

The formula to solve for the mass defect is:

md = (mp + mn) - mo

md = (2x 1.00728 + 2x1.00867) - 4.002603

md = 0.029297

Therefore, the mass defect is 0.029297 amu