1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
|
{
"metadata": {
"name": ""
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 8:Conducting Materials"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 8.1, Page 266"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#Variable declaration\n",
"n = 5.8*1e28; # Electrons density in electrons per cube meter\n",
"rho = 1.58*1e-8; #Resistivity of wire in ohm meter\n",
"m = 9.1*1e-31; # Mass of electron \n",
"e = 1.6*1e-19; # Charge of electron in coloumb\n",
"E = 1e2; # Electric field\n",
"\n",
"#Calculations\n",
"t = round((m/(rho*n*e**2))/1e-14);\n",
"u = (e*t*10**-14)/m;\n",
"v = u*E; \n",
"\n",
"#Results\n",
"print 'The relaxation time is ',t,'*10^-14 s'\n",
"print 'The mobility of electrons ',round(u/1e-3,2),'*10^-3 m^2/volt sec'\n",
"print 'The average drift velocity for an electric field of 1V/cm is ',round(v,3),'m/s'\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The relaxation time is 4.0 *10^-14 s\n",
"The mobility of electrons 7.03 *10^-3 m^2/volt sec\n",
"The average drift velocity for an electric field of 1V/cm is 0.703 m/s\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 8.2, Page 267"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from math import sqrt\n",
"\n",
"#Variable declaration\n",
"e = 1.6*1e-19; # Charge on electron in coulumb\n",
"m = 9.1*1e-31; # Mass of electron in kg \n",
"rho = 1.54*1e-8; #Resistivity of material at room temperature in ohm . meter\n",
"n = 5.8*1e28; # Number of electrons per cubic meter\n",
"Ef = 5.5; # The fermi energy of the conductor in eV\n",
"\n",
"#Calculations\n",
"vf = sqrt((2*Ef*e)/m);\n",
"t = (m/(n*e**2*rho));\n",
"MFP = vf*t;\n",
"\n",
"#Results\n",
"print 'Velocity of electron is',round(vf/1e6,2),'*10^6 m/s'\n",
"print 'Mean free path of electron is',round(MFP/1e-8,2),'*10^-8 m'\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Velocity of electron is 1.39 *10^6 m/s\n",
"Mean free path of electron is 5.53 *10^-8 m\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 8.3, Page 267"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#Variable declaration\n",
"m = 9.1*1e-31; #Mass of electron in kg\n",
"e = 1.6*1e-19; # Charge on electron in coulumb\n",
"t = 3*1e-14; # Relaxation time in seconds\n",
"n = 5.8*1e28; #Number of electrons in cubic meter\n",
"\n",
"#Calculations\n",
"rho =m/(n*t*e*e);#The resistivity of metal \n",
"u = 1/(n*e*rho);#The mobility of electron \n",
"\n",
"#Result\n",
"print 'The resistivity of metal is',round(rho/1e-8,2),'*10^-8 Ohm.meter' #incorrect answer in textbook\n",
"print 'The mobility of electron is',round(u/1e-3,2),'*10^-3 sqaure meter per volt.second' \n",
"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The resistivity of metal is 2.04 *10^-8 Ohm.meter\n",
"The mobility of electron is 5.27 *10^-3 sqaure meter per volt.second\n"
]
}
],
"prompt_number": 3
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 8.4, Page 268"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from math import sqrt\n",
"\n",
"#Variable declaration\n",
"e = 1.6*1e-19; # Charge of electrons in coloumbs\n",
"m = 9.1*1e-31; # Mass of electrons in Kg\n",
"Ef = 7*e ; #Fermi energy in electrons volt\n",
"t = 3*1e-14; # Relaxation time in seconds\n",
"\n",
"#Calculations\n",
"vf = sqrt(Ef*2/m);\n",
"lamda = vf*t;#The mean free path of electrons \n",
"\n",
"#Result\n",
"print 'The mean free path of electrons is',round(lamda/1e-10),'A'\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The mean free path of electrons is 471.0 A\n"
]
}
],
"prompt_number": 4
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 8.5, Page 268"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#Variable declaration\n",
"rhoC = 1.65*1e-8; # Electrical resistivity of cpooer in ohm meter\n",
"rhoN = 14*1e-8; # Electrical resistivity of Nickel in ohm meter\n",
"T = 300; # Room temperature in kelvin\n",
"\n",
"#Calculations\n",
"KCu =(2.45*1e-8*T)/rhoC;#Thermal conductivity of Cu\n",
"KNi =2.45*1e-8*T/rhoN;#Thermal conductivity of Ni\n",
"\n",
"#Results\n",
"print 'Thermal conductivity of Cu is ',round(KCu),'W/(m*degree)' #incorrect answer in textbook\n",
"print 'Thermal conductivity of Ni is ',KNi,'W/(m*degree)'\n",
"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Thermal conductivity of Cu is 445.0 W/(m*degree)\n",
"Thermal conductivity of Ni is 52.5 W/(m*degree)\n"
]
}
],
"prompt_number": 5
}
],
"metadata": {}
}
]
}
|
