# Calculating sun mass e=mc^2

I am working on a question: Doing this, the Sun produces it luminosity, the 3.8 × 10^26 Joules
of energy it emits each second. Use this information to determine the percentage decrease of
the Suns mass over its total lifetime of 10 billion years.

It’s a multiple choice question and each answer is a ratio, as in the mass I calculate divided by the Sun’s mass (from what I believe it to be)

Here’s what I attempted:

My first thought was to use the equation E=mc^2 and I used E = 3.8 x 10^26 Joules and c = speed of light constant and then I solved for mass and got: 4.22807 x 10^9 kg

So I assume the answer I got is the mass that is lost per second by the Sun. So then I converted 10 billions years to seconds and multiplied the mass I got previously by this number (3.15569 x 10^17) and the result was 1.3342478e+27 kg

Then I took this result (1.3342478e+27 kg) and divided by Sun’s mass and got 0.0006 which is not an answer choice at all.

If anyone can help me, I’d appreciate it.

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