The contribution in the total current flowing through a semicondu… - Vidyadip

MCQ

The contribution in the total current flowing through a semiconductor due to electrons and holes are $\frac{3}{4}$ and $\frac{1}{4}$ respectively. If the drift velocity of electrons is $\frac{5}{2}$ times that of holes at this temperature, then the ratio of concentration of electrons and holes is

✓
$6 : 5$
B
$5:6$
C
$3 : 2$
D
$2 : 3$

✓

Answer

Correct option: A.

$6 : 5$

a
(a)As we know current density $J = nqv$
==> ${J_e} = {n_e}q{v_e}$ and ${J_h} = {n_h}q{v_h}$
==> $\frac{{{J_e}}}{{{J_h}}} = \frac{{{n_e}}}{{{n_h}}} \times \frac{{{v_e}}}{{{v_h}}}$ ==> $\frac{{3/4}}{{1/4}} = \frac{{{n_e}}}{{{n_h}}} \times \frac{5}{{20}}$ ==> $\frac{{{n_e}}}{{{n_h}}} = \frac{6}{5}$

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