Electrical Conductivity of Liquids

1) Electrical Conductivity is an intrinsic property of any given material. 

2) Volta made first electric cell in 1800 using Zinc and Copper plates dipped in Sulphuric acid. The cell he made is called a Volta cell in his honour. The word "voltage" is also derived from his name.

3) Process of coating one metal onto other by the process of electrolysis is called as "electroplating".

4) Uses of electroplating:

    a) To protect metals from corrosion by atmospheric air/moisture air/chemical environment.

    b) To increase conductivity.

    c) Ornaments & decoration items.

 

Kirchoff's Law for black body

This law states that at a given temperature, the ratio of emission power to the absorption power for a given wavelength is same for all bodies and is equal to the emissive power of a black body at the same temperature.

Energy emitted per square meter is eƛdƛ.

Energy absorbed per unit area is QƛdQ.

eƛ/aƛ = ∂Qƛ /∂ƛ = constant

where eƛ is emission power ; aƛ is absorptive power

∂Qƛ is energy falling on unit area per second within same wavelength range & temperature.

 

(∂Qƛ /∂ƛ) depends only on temperature and for a given temperature it is constant.

For a perfectly black body, aƛ = 1

Note: Kirchoffs law is true only for temperature radiation.