The probability that an electron in a metal occupies the Fermi-level at any temperature (> 0 K)

In a P-type silicon sample, the hole concentration is $$2.25\times10^{15}/cm^3$$. If the intrinsic carrier concentration is $$1.5\times10^{15}/cm^3$$ , the electron concentration is

A p-type silicon sample has a higher conductivity compared to an n-type sample having the same dopant concentration.

A small concentration of minority carries is injected into a homogeneous semiconductor crystal at one point. An electric field of 10 V/cm is applied across the crystal and this moves the minority carriers a distance of 1 cm is 20 $$\mu$$ sec. The mobility (in cm²/volt-sec) will be