CBSE Class 12-science Answered

conductivity is the ability of a material to conduct electric current. The principle by which instruments measure conductivity is simple - two plates are placed in the sample, a potential is applied across the plates (normally a sine wave voltage), and the current is measured. Conductivity (G), the inverse of resistivity (R) is determined from the voltage and current values according to Ohm's law. 

G = I/R = I (amps) / E (volts)

Since the charge on ions in solution facilities the conductance of electrical current, the conductivity of a solution is proportional to its ion concentration. In some situations, however, conductivity may not correlate directly to concentration.

Specific conductivity (C) is simply the product of measured conductivity (G) and the electrode cell constant (L/A), where L is the length of the column of liquid between the electrode and A is the area of the electrodes (see Figure 1).  

C = G x (L/A)

If the cell constant is 1 cm-1, the specific conductivity is the same as the measured conductivity of the solution.