Getting Naan error while integrating with multiple parameters

Hi, I am evaluating spectral radiance of a black body. It is giving me NaaN errors. The following is th

B =

h=6.63*(10^-34);
k=1.381*(10^-23);
c=3*(10^8);
T=6000;
fun = @(x) (2*h*(x.^3))./(c*c*((exp((h*x)./(k*T))-1)));    

x=integral(fun,380*(10^-9),750*(10^-9));

Warning: Inf or NaN value encountered.

Answer 1

[VBBV]

h=6.63*(10^-34);
k=1.381*(10^-23);
c=3*(10^8);
T=6000;
fun = @(x) (2*h*(c.^2)).*(x.^(-5)).*(exp((h.*c)./(k*x*T))-1).^(-1);    
x=integral(fun,380*(10^-9),750*(10^-9))

May be the equation you wrote is typed incorrectly. Check this link for planks law for black body/ solar radiation https://www.google.com/search?q=solar+irradiance+formula&prmd=isvn&source=lnms&tbm=isch&sa=X&ved=2ahUKEwjQrZfhw9_9AhUEcGwGHd9ZAnAQ_AUoAXoECAIQAQ&biw=360&bih=676&dpr=2#imgrc=kK2Z1urXtXRX2M&lnspr=W10=

[Aakash Munnangi]

I was able to correct it. here is the code. However, the energy version of Planks law definite integral giving valuee of 0. I think I am missing some precision. need help.

working version with wave lengths

h=6.63*(10^-34);
k=1.381*(10^-23);
c=3*(10^8);
T=6000;
lambda1 = 380*10^-9;
lambda2= 750*10^-9;
M_e = @(x) (2 * pi * h * c^2) ./ (x.^5 .* (exp((h * c)./(x * k * T)) - 1));
M_e_int1 = integral(M_e,lambda1,lambda2)

lambda1 = 0;
lambda2= Inf;
M_e = @(x) (2 * pi * h * c^2) ./ (x.^5 .* (exp((h * c)./(x * k * T)) - 1));
M_e_int2 = integral(M_e,lambda1,lambda2)

fraction_of_energy = M_e_int1/M_e_int2;

//Not working or giving value of 0 , for energy version of planc law integration.

h=6.63*(10^-34);
k=1.381*(10^-23);
c=3*(10^8);
T=6000;        
Energy_lower_limit = 100;
Energy_upper_limit = 10000;
M_e = @(x) (x.^3.*2)./((h^3 * c^2)*((exp(x/(k * T)) - 1)));
M_e_int1 = integral(M_e, Energy_lower_limit, Energy_upper_limit)

[VBBV]

The energy version of planks law you are using may be incorrect. Check the values of input limits for energy being considered. Are they in same units ? Can you open a new question ?