Final_Sec1_S08

Final_Sec1_S08 - MatE 153 MatE 153 Section 1 FINAL Spring...

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Unformatted text preview: MatE 153 MatE 153 Section 1 FINAL Spring 2008 I have not received any information about the questions on this test prior to the exam. During the exam, I will only utilize the provided material and a calculator. During the exam, I will not receive any information from fellow students or utilize any materials such as notes or the textbook. PRINT NAME: ____________________________ SIGNATURE : _____________________________ PARTIAL CREDIT WILL ONLY BE GIVEN IF YOU SHOW ALL YOUR WORK NEATLY!! YOU WILL LOSE POINTS IF YOU DO NOT INCLUDE THE UNITS!! 1 MatE 153 Score: ______ / 100 1. Using text or a diagram, explain how the Hall effect can be used to determine carrier type. (10 points) 2. What is the remnant magnetization? (5 points) 2 MatE 153 3. Why do electrons and holes drift across a pn junction when there is no applied voltage? (5 points) 4. Describe in words (no equations) the meanings of n(E), g(E), and f(E). (5 points) 3 MatE 153 5. You are designing a piece of equipment where you want to limit the current that flows through a certain section. You have chosen to do this by increasing the resistance of a wire in that section. Name 4 ways you can increase the resistance of that section of wire: (5 points) i. ii. iii. iv. 6. Using a diagram or words (no equations), explain the difference between a Fermi energy in a metal versus a semiconductor. (5 points) 4 MatE 153 7. What is the drift velocity of an electron in a platinum (Pt) wire that is 0.2 m long, heated to 400K and has 4V dropped across it? Assume Pt has 2 valence electrons. (15 points) 5 MatE 153 8. The momentum of light shone on an electron in a well is 1.8 ×10-34 kg m/s. This excites the electron from the ground state to the 3rd energy level. What is the size of the well? (10 points) 6 MatE 153 9. Si is doped with 1018 atoms/cm3 of P (from Column V). Calculate the Fermi energy (relative to the intrinsic value) at 100K. (15 points) 7 MatE 153 10. A silicon sample that is 2 cm long and has a cross sectional area of 3 cm2 is doped with Al (from Column III) at 5 × 1018 cm-3 and Sb (from Column V) at 4 × 1018 cm-3. Your sample is at room temperature (300K). Assume all the dopants are ionized. What is the resistance of the doped sample? (10 points) 8 MatE 153 11. You have a solenoid that has 15 coils in 0.1 cm and has a current of 3A in it. a. What is the magnetic permeability of the sample if the total magnetization B is 4.5×10-2 Wb/m2? (12 points) b. Is the sample above paramagnetic or diamagnetic? (3 points) ________________ 9 ...
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