High School

The diameter of a white blood cell is 0.000591 in. Which of the following is this number written in scientific notation?

A. [tex]0.591 \times 10^{-3}[/tex] in
B. [tex]591 \times 10^{-6}[/tex] in
C. [tex]59.1 \times 10^{-5}[/tex] in
D. [tex]5.91 \times 10^{-4}[/tex] in

Answer :

To write the diameter of a white blood cell, 0.000591 inches, in scientific notation, we need to express it as a number between 1 and 10 multiplied by a power of 10.

Here’s the step-by-step process:

1. Identify the Significant Figures: The number we need to convert is 0.000591. Notice the significant figures here, which are 5, 9, and 1.

2. Convert to Scientific Notation:
- Move the decimal point to the right until you have a number between 1 and 10. For 0.000591, we move the decimal point 4 places to the right, which gives us 5.91.
- Count the number of places moved. In this case, it is 4 places.

3. Determine the Power of 10:
- Since we moved the decimal point 4 places to the right, we express this movement as a negative power of 10 because the original number is less than 1.
- Thus, the power of 10 will be [tex]\(-4\)[/tex].

4. Write the Number in Scientific Notation:
- Combine the number and the power of ten: [tex]\(5.91 \times 10^{-4}\)[/tex].

Therefore, 0.000591 inches written in scientific notation is [tex]\(5.91 \times 10^{-4}\)[/tex] inches, which matches the option given as [tex]$5.91 \times 10^{-4}$[/tex] in.