Question

A potential difference V is applied across a conductor of length L and diameter D. How is the drift velocity, v_d, of charge carriers in the conductor affected when (i) V is halved, (ii) L is doubled and (iii) D is halved ? justify your answer in each case.

Answer 1

We know drift velocity is given by

`|"V"_"d"| = "eτ"/"m" "E"`

Also `"E" = "V"/"L"`

So `|"v"_"d"| = "eτ"/"m"("V"/"L")`

(i) When V is halved drift velocity (v_d) gets halved

(ii) When L is doubled drift velocity (v_d) gets halved

(iii) When D is halved drift velocity (v_d) remains same.