Question

In tin at room temperature, the mobility of mobile electrons is about 1.5 ✕ 10⁻³ (m/s)/(V/m), and there are about 3.7 ✕ 10²⁸ mobile electrons per m³. Calculate the conductivity σ. In actual practice, it is usually easier to measure the conductivity σ and deduce the mobility u from this measurement.

Answer 1

Answer:

$\sigma = 8.88 \times 10^6 \frac{1}{ohm-m}$

Explanation:

As we know that mobility of electrons is given as

$\mu = \frac{v_d}{E}$

now we also know that

$j = \sigma E$

here we know

$j = ne v_d$

$ne v_d = \sigma E$

so we have

$\sigma = ne \frac{v_d}{E}$

$\sigma = (3.7 \times 10^{28})(1.6 \times 10^{-19})(1.5 \times 10^{-3})$

$\sigma = 8.88 \times 10^6 \frac{1}{ohm-m}$