A star similar to our sun radiates energy at the prodigious rate of 4.2 x 1026 W.
(a) At what rate does this star convert mass into energy?
kg/s
(b) Assuming that the star has radiated at this same rate for its entire lifetime of 4.6 x 109 y, and that its current mass is 2.5 x 1030 kg, what percentage of its original mass has been converted to energy?
%