전자재료및소자 - 숙제1 (Chapter 2), Due October 3th (e-campus과제에 올릴것) (책에 있는 연습문제
입니다.)
연습문제 2.2 a, b, c
2.2 Electrical conduction The resistivity of aluminum at 25 C has been measured to be 2.72  108  m. The thermal
coefficient of resistivity of aluminum at 0 C is 4.29  103 K1. Aluminum has a valency of 3, a density of 2.70 g cm3, and an
atomic mass of 27.
a.
Calculate the resistivity of aluminum at ─40ºC.
b.
What is the thermal coefficient of resistivity at ─40ºC?
c.
Estimate the mean free time between collisions for the conduction electrons in aluminum at 25 C, and hence estimate their
drift mobility.
연습문제 2.3
2.3 Conduction in gold Gold is in the same group as Cu and Ag. Assuming that each Au atom donates one conduct
ion electron, calculate the drift mobility of the electrons in gold at 22 C. What is the mean free path of the conducti
on electrons if their mean speed is 1.4 × 10 6 m s−1? (Use ρo and αo in Table 2.1.)
연습문제 2.14 a, b
2.14 Hall effect and the Drude model, Table 2.14 shows the experimentally measured Hall coefficient and resisitiviti
es for various metals and their position in the periodic table. (a) Calculate the Hall mobility for each element. (b) Calc
ulate the conduction electron concentration from the experimental value of RH.
Table 2.14 Measured Hall coefficients for a few metals at 25 C
Li
Na
K
Cs
Cu
Ag
Au
Ca
Mg
Group
I
I
I
I
IB
IB
IB
IIA
IIA
RH (×1011 m3 C1)









 (n m)









Zn
Al
In
III
III






IIB
Note: Data from various sources combined, including C. Hurd, The Hall Coefficient of Metals and Alloys, Plenum, New York,
1972.
연습문제 2.22
2.22 Strain gauges Consider a strain gauge that consists of a nichrome wire of resistivity 1100 n m, TCR () = 0.0
004 K1, a total length of 25 cm, and a diameter of 50 m. What is R for a strain of 103? For nichrome,  0.3.
What is R if there is a temperature variation of 1 C, given that the linear thermal expansion coefficient is 15 ppm
K1?
연습문제 2.28
2.28 Thermal resistance Consider a thin insulating disc made of mica to electrically insulate a semiconductor device
from a conducting heat sink. Mica has  = 0.75 W m1 K1. The disk thickness is 0.1 mm, and the diameter is 10 m
m. What is the thermal resistance of the disk? What is the temperature drop across the disk if the heat current through
it is 5 W?