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Explain the term 'drift velocity' of electrons in a conductor. Hence obtainthe expression for the current through a conductor in terms of drift - Temperature T velocity. |
Answer» Solution : Consider a CONDUCTOR of uniform cross-section AREA A, carrying a current I. Consider a SMALL section KL of the conductor having a length `Delta x `or having a VOLUME A. `Delta x` , then number of free electrons present in this section =` n A. Delta x `, where n = Number density of free electrons. Total charge carried by these electrons while CROSSING the given section `DeltaQ = n A: Deltax.e` and total time taken by the electrons to cross this section is `Delta t = (Delta x)/(v_d)`where `v_d = `drift velocity of electrons ` therefore I= (Delta Q)/(Delta t) = (nA Delta x.e)/((Deltax)/(v_d)) = nAev_d`. which is the requisite relation. |
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