Question

what is the scientific notation for 0.00215?
a 215×10⁻⁵
b 2.15×10⁻³
c 0.215×10⁻²
d 21.5×10⁻⁴

Explanation:

Step1: Recall scientific - notation form

Scientific notation is $a\times10^{n}$, where $1\leq|a|\lt10$ and $n$ is an integer.

Step2: Move the decimal point

For the number $0.00215$, move the decimal point 3 places to the right to get a number between 1 and 10. So, $a = 2.15$.

Step3: Determine the exponent

Since we moved the decimal point 3 places to the right, $n=- 3$. So, $0.00215 = 2.15\times10^{-3}$.

Answer:

B. $2.15\times10^{-3}$