The basic principle of cotterell precipitator is

The basic principle of Cottrell 's precipitator is

The cotterells precipittor is used to :

The basic principle of zone refining is -

What is the principle of selective precipitations ?

The basic principle of hydrogen economy is

Particulate matter in polluted air is removed by the application of electrostatic precipitator. Explain the working principle of electrostatic precipitator.

Give the basic principle of potentiometer.