**In this article, we will learn the mathematical equation required to calculate level in the tank. **

**I already have covered an article on radar level measurement. you can click here to read more on it.**

**We know that now a days SMART transmitters are used which contain an inbuilt microprocessor and they carry on calculation and all other tasks by own but, to know how actually that level has come it is important to know the logic behind it.**

**In radar level measurement radio waves are used. and radio waves are electromagnetic waves. **

**Radio waves travel at the velocity of light 2" 2.9979 x 10 rest to 8 meters per second in a perfect vacuum.**

**A formula relating wave velocity to relative permittivity (the ratio of a substance's permittivity to that of a perfect vacuum, symbolized as εr and sometimes called the dielectric constant of the substance) and the velocity of light in a perfect vacuum (c)**

**is shown here : **

where Er is,

**In the above-mentined image, you can see two-tank having difference interface liquid contain different relative permittivity.**

**Simply, put all the value in the above-mentioned equation and you will have your desire result then match it with a value of the transmitter display.**