The number of significant figures in $200.40$ is

The number of significant figures in the numbers $4.8000 \times 10^{4}$ and $48000.50$ are respectively

Which is the best method to determine significant numbers?

"Changing the units of measurement does not change the number of significant figures." Explain with an example.

Length,breadth,and thickness of a strip having a uniform cross-section are measured to be $10.5 \ cm$,$0.05 \ mm$,and $6.0 \ \mu m$,respectively. Which of the following option$(s)$ give$(s)$ the volume of the strip in $cm^3$ with correct significant figures?

What are significant figures? What are significant digits? Explain with examples.