(a) Show that, for any source radiating power , the rate at which its mass decreases…

PHYSICS · Multi-part · A Level · Physics · Nuclear physics · Nuclear physics

Problem

(a) Show that, for any source radiating power

P

, the rate at which its mass decreases is given by

\displaystyle \frac{dm}{dt} = -\frac{P}{c^{2}}

. (b) The Sun’s total power output (solar luminosity) is

3.8\times10^{26}\,\text{W}

and its mass is

2.0\times10^{30}\,\text{kg}

. Using

c = 3.0\times10^8\,\text{m\,s}^{-1}

, (i) Calculate the mass lost by the Sun each second due to radiation. (ii) Determine the fractional mass loss of the Sun in one year and comment on its significance in comparison with the Sun’s total mass.

Related theory

Mass-Energy Equivalence
Mass defect and binding energy
Nuclear physics
Mass-energy relation
Nuclei

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