Question

If the rest energies of a positive sigma particle and a lambda particle are 1189.4 and 1115.7 Mev respectively, what is the difference in their masses in kilograms?

Answer 1

Answer:

1.31022×10⁻³⁴ kg

Explanation:

Difference in energies = 1189.4-1115.7 MeV = 73.7 MeV

Convert this energy to Joules

1 MeV = 1.6×10⁻¹⁹ J

73.7 MeV = 73.7×1.6×10⁻¹⁹ J = 117.92×10⁻¹⁹ J

c = Speed of light = 3×10⁸ m/s

From Einstein's equation

E = mc²

$m=\frac{E}{c^2}\\\Rightarrow m=\frac{117.92\times 10^{-19}}{(3\times 10^8)^2}\\\Rightarrow m=1.31022\times 10^{-34}\ kg$

∴ Difference in their masses is 1.31022×10⁻³⁴ kg