How to plot or overlay graphs of a function with two variables using matplotlib?

I am having difficulty finding the correct graph in my plot, I am modeling two equations of physics of two variables, I believe that the problem is because I am not correctly traversing the graph with my while, since they are two functions that depend on two variables, where I observe the variation of one, keeping the other fixed and generating the graph. I believe I am not being able to go through both properly and it generates results a lot discrepancies to the expected Model.

import math
from matplotlib import pyplot as plt


h = 1.05457168 * 10**(-34) # J * s - Constante de Planck
c = 299792458 #m/s - Velocidade da Luz
k= 1380649 * (10**(-23)) # J/K - Constante de Boltzmann 
T = -248 #Kelvin / 25 celsius  - Temperatura do Sistema em Kelvin
i = 0.000004 # Comprimento de onda variável, começando em 400nm 
ni = (c/i) # Frequência de oscilação da onda eletromagnética

Radiancias=[] # Valores da radiância em função da temperatura e do comprimento de onda
Temperaturas=[] # Valores de temperatura 
Densidadesespectrais=[] # Valores da densidade espectral em função do comprimento de onda e temperatura
wavelens=[] # Valores para o comprimento de onda


while (T<=6000) and (i<=0.000007):
    # 1. Radiândia em função da energia e da temperatura
    R = ((2 * math.pi * (c**2))/(i * (math.exp((c * h) /(k * i * T) -1))))
    # 2. Densidade de energia espectral por temperatura e frequência de oscilação
    u = ((8 * math.pi * h * ni)/(c**3)) * ((1)/(math.exp((h * ni)/(k * T))- 1))
    Radiancias.append(R)
    Densidadesespectrais.append(u)
    Temperaturas.append(T)
    wavelens.append(c/ni)
    T=T+10
    i=i+0.0000001

plt.plot(Radiancias, Temperaturas, color='blue', marker = 'o', linestyle = 'solid')
plt.plot(Radiancias, wavelens, color='red', marker = 'o', linestyle = 'solid')
plt.plot(Densidadesespectrais, wavelens, color='green', marker='o', linestyle = 'solid')
plt.plot(Densidadesespectrais, Temperaturas, color='green', marker='o', linestyle = 'solid')

All the graphs are coming out as straight and I'm not sure if it was because I built the code in such a way that it only loops through one variable at a time and I can't accumulate values as a function of the two variables (wavelength and temperature)

This is what I'm finding with the Code

And this was the expected result for spectral densities as a function of wavelength would be that ->