Ap-n step junction in si has 1018 cm-3 net acceptors on the p side and 1014 cm-3 net donors on the n side. assume t = 300k, ni = 1.5 x 1010cm-3, find (a) the built-in potential and (b) extent of depletion region on n and p side. (c) explain how the built-in potential is related to the fermi level and what happens to vbi as a function of temperature in the range 30k to 500k.

What is the name for the remnant of an asymptotic giant that has lost its shells? black dwarf white dwarf yellow giant black hole

Consider a double atwood machine constructed as follows: a mass 4m is suspended from a string that passes over a massless pulley on frictionless bearings. the other end of this string supports a second similar pulley, over which passes a second string supporting a mass of 3m at one end and m at the other. using two suitable generalized coordinates, set up the lagrangian and use the lagrange equations to find the acceleration of the mass 4m when the system is released. explain why the top pulley rotates even though it carries equal weights on each side.

Find v1, the speed of the fluid in the left end of the main pipe. express your answer in terms of h1, h2, g, and either a1 and a2 or γ, which is equal to a1a2.