The density of a material is 0.8 g cm³. Express it in Sl units.

The correct option is 800 kg m^-3.

To convert the density from CGS units (grams per cubic centimeter, or g cm^-3) to SI units (kilograms per cubic meter, or kg m^-3), we can use the standard conversion factors for mass and volume.

First, let's write down the relationships between the units:
1. Conversion factor for mass from grams (g) to kilograms (kg):
$$1\text{ g}={10}^{-3}\text{ kg}$$
2. Conversion factor for length from centimeters (cm) to meters (m):
$$1\text{ cm}={10}^{-2}\text{ m}$$

Now, let's find the conversion factor for volume from cubic centimeters (cm³) to cubic meters (m³):
$$1{\text{ cm}}^3={\left({10}^{-2}\text{ m}\right)}^3={10}^{-6}{\text{ m}}^3$$

Using these conversion factors, we can express 1 g cm^-3 in terms of kg m^-3:
$$1\text{ g }{\text{cm}}^{-3}=\frac{1\text{ g}}{1{\text{ cm}}^3}=\frac{{10}^{-3}\text{ kg}}{{10}^{-6}{\text{ m}}^3}={10}^3\text{ kg }{\text{m}}^{-3}=1000\text{ kg }{\text{m}}^{-3}$$

Given that the density of the material is 0.8 g cm^-3, we multiply this value by the conversion factor:
$$\text{Density}=0.8\times 1000\text{ kg }{\text{m}}^{-3}=800\text{ kg }{\text{m}}^{-3}$$

Thus, the density of the material in SI units is 800 kg m^-3.