And gaas and alp the data table

7  Composition (at% Zn)  Questions and Problems  ●  395  



10  20  30  


6 


5  
4 


3  
2  
1  
0  

10  20  30  40 
are 1.5 free electrons per gold atom. The electrical conductivity and density for Au  

are 4.3 � 107(�m)�1and 19.32 g/cm3, re  this alloy given the following data:  
spectively. (b) Now compute the electron  
Electrical  
12.15  
From Figure 12.35, estimate the value of A in Equation 12.11 for zinc as an impurity  
Phase 


12.16 

�  1.88 � 10�8  8.94  
(a) Using the data in Figure 12.8, determine  �  5.32 � 10�7  8.25  
the values of �0 and a from Equation 12.10 for pure copper. Take the temperature T  12.19  The roomtemperature electrical resistivities of pure lead and pure tin are 2.06 �  


Figure 12.8. (c) Using the results of parts a and b, estimate the electrical resistivity of  


12.17  
Determine the electrical conductivity of a  
CuNi alloy that has a yield strength of 125  
MPa (18,000 psi). You will find Figure  
12.18 


Tin bronze has a composition of 92 wt% Cu and 8 wt% Sn, and consists of two phases  


at room temperature: an � phase, which is copper containing a very small amount of  
tin in solid solution, and an � phase, which 
396  ●  12.27  



12.21 

12.28  
tion involving an acceptor impurity atom.  




12.22  
N  Si  
B  Ge  

(12.38)  
Zn  GaAs  
S  InSb  
In  CdS  
As  ZnTe  

12.29  
12.23  12.30  
Thus, a plot of the intrinsic ln n (or ln p)  







12.24  12.31  


12.25 


For each of the following pairs of semicon  
ductors, decide which will have the smaller  


12.26  12.32 


free electrons in numbers in excess of those  



