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Unformatted text preview: MatE 153
MatE 153 Section 1
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
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)
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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- Fall '08