Question

1 atomic mass unit is equivalent to

• A. 39 MeV
• B. 93 MeV
• C. 139 MeV
• D. 931 MeV

Answer 1

Answer: (D)

931 MeV

1 amu = mass of 1 particle of a substance. Mass of 1 mole of a substance = 1 amu times no. of atoms in a mole.
Thus, $1amu=\frac{1}{6.022\times {10}^{23}}=1.66\times {10}^{-24}g=1.66\times {10}^{-27}kg$
Thus, $E=1.66\times {10}^{-27}kg\times (299792458{)}^2=1.49241783\times {10}^{-10}J$
Thus, $1amu=1.49241783\times {10}^{-10}J$
To convert it to MeV, divide by $1.60217653\times {10}^{-13}$ to get $1amu=931MeV$