Question

If the sun radiates energy at the rate of 4 x 10^26 Js^-1, what is the rate at which its mass is decreasing?

(a) 5.54 x 10^9 kgs^-1

(b) 4.44 x 10^9 kgs^-1

(c) 3.44 x 10^9 kgs^-1

(d) 2.44 x 10^9 kgs^-1

The question was asked during an interview for a job.

I would like to ask this question from Einstein’s Special Theory of Relativity in portion Ultrasonics & Relativity of Engineering Physics I

Answer 1

Correct option is (b) 4.44 x 10^9 kgs^-1

The best I can explain: As we know from Einstein’s mass energy relation, E = mc^2.

Therefore, ΔE= Δmc^2

ΔE = 4 x 10^26 Js^-1, c = 3 x 10^8 ms^-1.

Δm = 4 x 10^26 Js^-1/ 9 x 10^16m^2s^-2

Δm = 4.44 x 10^9 kgs^-1.