Problem 1: Classical Theory of Conduction Find (a) the current density and (b) the drift velocity if there is a current of 1 mAin Number 14 copper wire (diameter = 0.163 cm).

Problem 2: Classical Theory of Conduction
How long would it take for an electron to travel a city block (~160 m) if it were moving through a #10 Cu wire (0.102 inches dia) with 10 volts across its end. Use a Cu resistivity of 1.7 μW cm and carrier density of 9 X 10²² cm-³.

Problem 3: Quantum Theory of Conduction What is the Fermi speed, that is the speed of a conduction electron whose energy is equal to the Fermi energy for Na, Au, and Sn.
See Table 10.2(3) in tippler.

Problem 4: Band Diagram
Draw simple band diagrams with appropriate labels (Ef, Ec, Ev) for a metal and a p-type semiconductor. Include the dopant energy level for the semiconductor. Explain how and why the resistivity of each material changes as the temperature increases.

Problem 5: Semiconductor Dopants
(a) What are donor and acceptor impurities in a semiconductor and why are they used?
(b) If a donor dopant is to be thermally ionized at room temperature, then how far can its energy level be located below the conduction band (in eV).

Problem 6: Hall Effect
When a p-type silicon device (2 mm wide, 10 cm long, 350 um thick) is placed in a 3 Tesla perpendicular magnetic field and 1 A flows along its length, a Hall voltage of 50 μV is measured across its width. Find the carrier density of this device. Also, draw a picture of the device with the F qv X B and the Hall voltage polarity indicated (+ and -), assuming that the B field points into of the page and the current flows right to left.

Problem 7: Devices
Briefly describe an LED and solar cell. Include simple band diagrams of each that show the electron transitions due to the interacting photon.

Problem 8: pn Diode
Find the room temperature resistance of a Si diode at 0.8V in forward and reverse bias. Assume I0 = 0.1 μA and kT = 26 meV at room temperature. By referring to your results for these resistances, explain why a diode is "rectifying" or a one-way device.

Problem 1: Classical Theory of Conduction Find (a) the current dens...