Calculate the built-in potential barrier, Vbi, for Si, Ge, and GaAs pn junctions if they each have the following dopantconcentrations at T = 300 It(a) Nd = 1014 cm—3 Na = 1017 cm-3(b) Nd =5 x 1016 Na = 5 x 1016(c) Nd = 1017 Na = 1017

Consider a large isothermal enclosure that is maintained at a uniform temperature of 2000 k. calculate the emissive power of the radiation that emerges from a small aperture on the enclosure surface. what is the wavelength ? , below which 10% of the emission is concentrated? what is the wavelength ? 2 above which 10% of the emission is concentrated? determine the wavelength at which maximum spectral emissive power occurs. what is the irradiation incident on a small object placed inside the enclosure?

Water at the rate of 1 kg/s is forced through a tube with a 2.5 cm inner diameter. the inlet water temperature is 15°c, and the outlet water temperature is 50°c. the tube wall temperature is 14°c higher than the local water temperature all along the length of the tube. what is the length of the tube?

How to increase the thermal officiency of an ideal simple rankino cycle? among these methods, which one is the best and why?