The diagram depicts a stage micrometer, with divisions $0.10\,\text{mm}$ apart, as seen through an eyepiece that contains a graticule. The microscope’s field of view area may be worked out by using the formula $\text{area} = \pi r^2$. Using the information given and taking $\pi$ as $3.142$, a student found the area of the microscope’s field of view. Which answer has been rounded correctly to an appropriate number of significant figures?
- A$0.04909\,\text{mm}^2$
- B$5 \times 10^{-2}\,\text{mm}^2$
- C$4.909 \times 10^4\,\mu\text{m}^2$
- D$4.91 \times 10^4\,\mu\text{m}^2$