To Determine the Wein’s Constant from Planck’s Law .

To Determine the Wein’s Constant from Planck’s Law .

PROGRAM :

clf ,clc
h = 6.626e-34
c = 3e8
k = 1.38e-23
lambda = linspace(1e-7,1.5e-5,1000)'
T = [500:100:1000]
function y=f(lambda, T)
 y = (8*%pi*h*c)/((lambda^5)*(exp((h*c)/(lambda*k*T))-1))
endfunction
lambda_max = []
for t = T
 y = feval(lambda,t,f)
 [peak,index] = max(y)
 lambda_max = [lambda_max,lambda(index)]
end
x= 1./T
plot(x,lambda_max,"*k","linewidth",3)
[a,b,sig] = reglin(x,lambda_max)
disp("Weins constant is "+string(a)+" m.K")
y = (a*x)+b
plot(x,y,"-k")
legend(["Original Data","Fitted Curve"],2)
xlabel("1/T(K^-1)","font_size",4)
ylabel("Wavelength with maximum energy density (m)","font_size",4)
title("Original Data and Fitted Curve to determine Weins constant.","font_size",4)
xgrid

output:

 "Weins constant is 0.0028968 m.K"