Write the mathematical relation between Mobility And Drift Velocity of charge carriers in a conductor.

Electron mobility is the drift velocity per unit strength of the electric field applied across the conductor. It is denoted by \(\mu\).

  • The SI unit of electron mobility is meter2volt-1second-1 (m2V-1s-1).
  • The mathematical relation between mobility and drift velocity of charge carriers is given by the formula:

\(\mu = {V_d \over E}\)

  • where, Vd refers to the drift velocity by free electrons on applying an electric field.
  • and E denotes an Electric field.

Related Questions

  1. Define mobility of electron.
  2. Give two examples of drift velocity.
  3. Explain the relation between current and drift velocity.
  4. Define the drift velocity of electrons in a conductor?
  5. What is the relation between drift velocity and electric field?
  6. Define relaxation time of the free electrons drifting in a conductor? How is it related to the drift velocity of free electrons? Use this relation to deduce the expression for the electrical resistivity of the material.
  7. Two conducting wires X and Y of the same diameter but different materials are joined in series across a battery. If the number density of electrons in X is twice that in Y, find the ratio of the drift velocity of electrons in the two wires.
  8. It is known that the drift velocity of electrons is only a few mm/s for a current of a few amperes. How is it possible that a current is established almost instantaneously when a circuit is closed? For example, a bulb glows as soon as the connection is switched on. Explain.

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CBSE CLASS XII Related Questions

  • 1.
    Read the following paragraph and answer the questions that follow.
    A p-type or n-type semiconductor can be converted into a p-n junction by doping it with suitable impurity. The motion of majority charge carriers causes diffusion current across the junction while the barrier electric field causes motion of minority carriers for drift current. In case of unbiased diode, the diffusion and drift currents are equal. This equilibrium is disturbed by the biasing batteries. Diodes, therefore, allow currents in one direction. This property of diode is used in making rectifiers.


      • 2.
        The resistance of a metal wire at \( 20^\circ \text{C} \) is \( 1.05 \, \Omega \) and at \( 100^\circ \text{C} \) is \( 1.38 \, \Omega \). Determine the temperature coefficient of resistivity of this metal.


          • 3.
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              • 4.
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                  • 5.
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                      • 6.
                        Read the following paragraph and answer the questions that follow.
                        In an experiment with convex lens of focal length f, the screen is fixed at a distance D from the object. A student slowly moves the lens away from the object towards the screen and finds that she is able to form sharp image of the object for two positions of the lens. The distance between these two positions of the lens is d.

                          CBSE CLASS XII Previous Year Papers

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