Roughly, it takes light less than 0.000000003 of a second to travel a one-meter distance. Express this number in the form of a × 10^n where 1 < a < 10 and is a one-digit number.

Question

A. 3 × 10^8

B. 3 × 10^9

C. 3 × 10^−8

D. 3 × 10^−9

Answer 1

To express the number in the form of a × 10^n, we need to move the decimal point to the right until we have a number between 1 and 10.

Starting with 0.000000003, we move the decimal point 9 places to the right to get 3.

This means the number can be expressed as 3 × 10^9.

Therefore, the correct answer is B. 3 × 10^9.