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 m2V-1s-1.
- The dimensional formula of mobility is [M-1L0T2A1].
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-
Also Read- Deriving Dimensional Formula of Electric Field
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- Deriving 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 carriers.
Test Your Concepts-
Quiz on Mobility of Charge Carriers
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