**Electric Current-**

Before you go through this article, make sure that you have gone through the previous article on **Mechanism of Current Flow**.

**We have learnt-**

- When a potential difference is applied across the ends of a conductor, an electric field is created inside it.
- The electric field applies an electric force on the free electrons inside it.
- As a result, they start drifting in a preferred direction and the flow of current starts.
- The drift velocity of free electrons is given by the formula-

**In this article, we will learn about mobility of charge carriers.**

**Mobility of Charge Carriers-**

The conductivity of any material is due to its mobile charge carriers. These may be-

- electrons in metals
- positive and negative ions in electrolytes
- electrons and holes in semiconductors

The mobility of a charge carrier is defined as the drift velocity acquired by it in a unit electric field. |

**The mobility of a charge carrier is denoted by the symbol μ and is given by the formula-**

**(Equation-01)**

**Characteristics-**

- The
**SI unit**of mobility is**m**.^{2}V^{-1}s^{-1} - The
**dimensional formula**of mobility is**[M**.^{-1}L^{0}T^{2}A^{1}]

**Deriving SI Unit Of Mobility-**

**From equation-01, the mobility of a charge carrier is given by-**

**So, SI unit of mobility is given by-**

**Deriving Dimensional Formula Of Mobility-**

**From equation-01, the mobility of a charge carrier is given by-**

**So, dimensional formula of mobility is given by-**

**Relation Between Electric Current & Mobility For A Conductor-**

**We know, the relation between electric current and drift velocity of charge carriers is given by-**

**(Equation-02)**

**Also Read-** **Derivation of Relation Between Electric Current & Drift Velocity**

**From equation-01, we have-**

**(Equation-03)**

**Using Equation-03 in Equation-02, we get-**

**This is the required relation between electric current and mobility of charge carrier.**

**Read the next article on-**

**Get more notes & other study material of the Chapter** **Current Electricity**.