Solution
= Solution
Using the same intrinsic-carrier approximation at $300\ \mathrm K$ gives
$$
\boxed{\frac{n_{i,\beta}}{n_{i,\alpha}}\simeq e^{0.1/(k_B300)}=47.85}.
$$
Similar <mass> density and coordination do not prove equal <electron> and <hole> effective masses; this result isolates the exponential band-gap effect.