Question

which is greater 1.62*10^-8 or 5.2*10^,8 and how

Answer 1

5.2 × 10^8
since the former has negative power, moves the point 8 times to the front, hereby lowering the value. the latter moves to point back, increasing the value.
And it u meant 5.2×10^-8, still 5.2 would be greater as both the 10^-8s can be cancelled out leaving just 1.62 and 5.2, of which the latter is the greater one.