Consider the following statements
(a) Electron and hole concentration in semiconductor at thermal equilibrium is related as ${\mathrm{n}}_{\mathrm{e}}{\mathrm{n}}_{\mathrm{h}}={\mathrm{n}}_{\mathrm{i}}^2$
(b) The approximate energy band gaps for Si and Ge are 1.1eV and 0.7eV respectively
(c) In n – type semiconductor, donor level is near to conduction band
(d) In p – type semiconductor, acceptor level is near to valence band
Choose the correct statements