50 POINTS AND BRAINLIEST PLS ANSWER FAST AND EXPLAIN YOUR ANSWER!!!!
PART A: The sun produces 3.9 ⋅ 10^33 ergs of radiant energy per second. How many ergs of radiant energy does the sun produce in 1.55 ⋅ 10^7 seconds?

PART B: Which is the more reasonable measurement of the diameter of a human hair:
1.8 ⋅ 10^−2 mm or 1.8 ⋅ 10^2 mm? Justify your answer.