Question

Which number is equivalent to 0.000 000 1 : 10^7 or 10^-7 and why

Answer 1

It would be 10^-7.

When you have a negative number in scientific notation, you count a whole zero and start counting behind the decimal point because a negative number is less than 0. So, it cannot have a value over 0. Though if it was after the decimal, it would be the positive answer because a positive number is higher than 0.

An example would be:
10^-3=0.001
10^3=1000