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// Scilab Code Ex 10.13 Thermionic emission of a filament: Page-352 (2010)
e = 1.6D-19; // Electronic charge, C
m = 9.1D-31; // Mass of the electron, kg
k = 1.38D-23; // Boltzmann constant, J/mol-K
h = 6.626D-34; // Plank's constant, Js
W = 4.5; // Work function of tungsten filament, eV
D = 1D-4; // Diameter of the filament, m
r = D/2; // Radius of the filament, m
T = 2400; // Temperature of the filament, K
l = 0.05; // Length of the filament, m
A = 4*%pi*e*m*k^2/h^3; // A constant expressed in ampere per metre square
// per kelvin square
a = 2*%pi*r*l; // Surface area of the filament, meter square
J = A*T^2*exp(-e*W/(k*T)); // Electronic current density of the filament,
// ampere per metre square
I = a*J; // Electric current due to thermionic emission, ampere
disp(I,"The electric current due to thermionic emission, in A, is : ");
// Result
// The electric current due to thermionic emission, in A, is :
// 0.0392404
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