what is mass density relative density optical density
Answers
1. Mass Density-
Mass density represents the mass (or number of particles) per unit volume of a substance, material or object. Most substances (especially gases) increase in density as their pressure increases or as their temperature decreases. Measuring the mass density of materials can predict a material’s inherent flaws, such as chances of corrosion.
Mass density is a quantitative expression of the amount of mass contained per unit volume. The standard unit is kilograms per meter cubed (kg/m3). The symbol most often used for density is (the Greek letter rho).
Mass density is also known as density.
2. Relative Density-
It is the of the (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity usually means relative density with respect to water. The term "relative density" is often preferred in scientific usage. It is defined as a ratio of density of particular substance with that of water.
If a substance's relative density is less than one then it is less dense than the reference; if greater than 1 then it is denser than the reference. If the relative density is exactly 1 then the densities are equal; that is, equal volumes of the two substances have the same mass. If the reference material is water then a substance with a relative density (or specific gravity) less than 1 will float in water. For example, an ice cube, with a relative density of about 0.91, will float. A substance with a relative density greater than 1 will sink.
Temperature and pressure must be specified for both the sample and the reference. Pressure is nearly always 1 (101.325 ). Where it is not, it is more usual to specify the density directly. Temperatures for both sample and reference vary from industry to industry. In British brewing practice the specific gravity as specified above is multiplied by 1000.Specific gravity is commonly used in industry as a simple means of obtaining information about the concentration of solutions of various materials such as , solutions
3. Optical Density
Optical density is a term used in the field of optical spectroscopy to describe the propagation of a wave through a material. Optical density is also referred to as the absorbance of the medium.
The value of the optical density is calculated as the logarithmic ratio of the radiation incident on the material to the radiation transmitted by the medium. The value of optical density is important in the field of analytical chemistry.
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✌Mass density✌
The mass per unit volume of a body or material. The mean density of a celestial body is its total mass divided by its total volume.
✌Relative density✌
The ratio of the density of a substance to the density of a standard, usually water for a liquid or solid, and air for a gas.
✌Optical density✌
The degree to which a refractive medium retards transmitted rays of light.