What is the number of significant figures in $11.118 \times 10^{-6} \ V$?

The radius of the Earth is $6371 \ km$ and the radius of its orbit around the Sun is $149 \times 10^6 \ km$. The order of magnitude of the diameter of the orbit is greater than that of the Earth by

The length of the side of a cube is $1.2 \times 10^{-2} \ m$. Its volume up to correct significant figures is

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

Each side of a metallic cube of mass $5.580 \text{ kg}$ is measured to be $9.0 \text{ cm}$. Keeping the significant figures in view, the density of the material of the cube can be best expressed as $X \times 10^3 \text{ kg m}^{-3}$, where the value of $X$ is:

"Trailing zeros in a number without a decimal point are not significant." Show that this statement is not always true.