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
|
{
"cells": [
{
"cell_type": "markdown",
"metadata": {},
"source": [
"#Chapter 2 , Energy Levels and Electron Emission"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 2.1 , Page Number 33 "
]
},
{
"cell_type": "code",
"execution_count": 4,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
" Emission current is 0.0166 A.\n"
]
}
],
"source": [
"import math\n",
"\n",
"#Variables\n",
"\n",
"phi = 3.4 #Voltage (in electron-volt)\n",
"e = 1.6 * 10**-19 #Charge on electron (in Coulomb)\n",
"A = 6.0 * 10**4 #Emission constant (in Ampere per meter-square per kelvin-square)\n",
"T = 2000.0 #Temperature (in kelvin)\n",
"l = 40.0 * 10**-3 #Length (in meter)\n",
"D = 0.2 * 10**-3 #Diameter (in meter)\n",
"k = 1.38 * 10**-23 #Boltzmann constant (in meter-square kilogram per second-square per kelvin)\n",
"\n",
"#Calculation\n",
"\n",
"b = phi * e /k #Constant \n",
"Js = A*T**2*math.exp(-b/T) #Emission current density (in Ampere per meter-square)\n",
"S = math.pi * D * l #Emitting surface (in meter-square)\n",
"I = Js * S #Emission current (in Ampere) \n",
"\n",
"#Result\n",
"\n",
"print \"Emission current is \",round(I,4),\" A.\"\n",
"\n",
"#Slight variation due to higher precision."
]
}
],
"metadata": {
"kernelspec": {
"display_name": "Python 2",
"language": "python",
"name": "python2"
},
"language_info": {
"codemirror_mode": {
"name": "ipython",
"version": 2
},
"file_extension": ".py",
"mimetype": "text/x-python",
"name": "python",
"nbconvert_exporter": "python",
"pygments_lexer": "ipython2",
"version": "2.7.10"
}
},
"nbformat": 4,
"nbformat_minor": 0
}
|
