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(A) In a semiconductor,as the temperature increases,the number of charge carriers $(n_e)$ increases exponentially due to the breaking of covalent bond

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$n_e$ increases and $v_d$ decreases

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(A) In a semiconductor,as the temperature increases,the number of charge carriers $(n_e)$ increases exponentially due to the breaking of covalent bonds.Since the current $I$ is given by $I = n_e e A v_d$,the drift velocity is expressed as $v_d = \frac{I}{n_e e A}$.As temperature increases,the scattering of electrons by lattice vibrations (phonons) increases,which leads to a decrease in the relaxation time $(	au)$.Since $v_d = \frac{eE	au}{m}$,the decrease in relaxation time causes the drift velocity $(v_d)$ to decrease.Therefore,$n_e$ increases and $v_d$ decreases.

Let $n_e$ be the number density of electrons and $v_d$ be the drift velocity in a semiconductor. When the temperature is increased:

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