Mobility of Charge Carriers

Write the mathematical relation between mobility and drift velocity of charge carriers in a conductor. Name the mobile charge carriers responsible for conduction of electric current in

Write the mathematical relation between mobility and drift velocity of charge carriers in a conductor. Name the mobile charge carriers responsible for conduction of electric current in

an electrolyte

A conductor of length $\text{'}l\text{'}$ is connected to a d.c. source of potential $\text{'}V\text{'}.$ If the length of the conductor is tripled, by stretching it, keeping $\text{'}V\text{'}$ constant, explain how do the following factors vary in the conductor : Resistivity.

A conductor of length $\text{'}l\text{'}$ is connected to a d.c. source of potential $\text{'}V\text{'}.$ If the length of the conductor is tripled, by stretching it, keeping $\text{'}V\text{'}$ constant, explain how do the following factors vary in the conductor :Resistance

A conductor of length $\text{'}l\text{'}$ is connected to a d.c. source of potential $\text{'}V\text{'}.$ If the length of the conductor is tripled, by stretching it, keeping $\text{'}V\text{'}$ constant, explain how do the following factors vary in the conductor : Drift speed of electrons

Define relaxation time of electrons in a conductor. Explain how it varies with increase in temperature of a conductor. State the relation between resistivity and relaxation time.

Are the paths of electrons straight lines between successive collisions (with positive ions of the metal) in the presence of electric field ? Establish a relation between drift velocity '$v_d$' of an electron in a conductor of cross-section $\text{'}A\text{'},$ carrying current $\text{'}I\text{'}$ and concentration $\text{'}n\text{'}$ of free electrons per unit volume of conductor. Hence obtain the relation between current density and drift velocity.

Are the paths of electrons straight lines between successive collisions (with positive ions of the metal) in the absence of electric field

What is meant by drift velocity of free electrons ? Derive Ohm's law on the basis of the theory of electron drift.

Prove that the current density of a metallic conductor is directly proportional to the drift speed of electrons.

Explain the term 'drift velocity' of electrons in a conductor. Hence obtain the expression for the current through a conductor in terms of 'drift velocity'.

Define the electrical resistivity of a material. How it is related to the electrical conductivity ? Of the factors, length, area of cross-section, nature of material and temperature - which ones control the resistivity value of conductor ?

Define the terms resistivity and conductivity and state their SI units. Draw a graph showing the variation of resistivity with temperature for a typical semiconductor.

Explain how the average velocity of free electrons in a metal at constant temperature, in an electric field, remains constant even though the electrons are being constantly accelerated by this electric field ?

Distinguish between electromotive force and terminal potential difference of a cell. What are their units ?

The earth's surface has a negative surface charge density of ${10}^{-9} {\mathrm{Cm}}^{-2}.$ The potential difference of $400 \mathrm{kV}$ between the top of the atmosphere and the surface results (due to the low conductivity of the lower atmosphere) in a current of only $1800 \mathrm{A}$ over the entire globe. If there were no mechanism of sustaining atmospheric electric field, how much time (roughly) would be required to neutralize the earth's surface? (This never happens in practice because there is a mechanism to replenish electric charges, namely the continual thunderstorms and lightning in different parts of the globe).(Radius of earth $= 6.37\times {10}^{6 }\mathrm{m}$).