Physics Assignment | MATLAB Code

Semi-infinite medium initially at Ti=0 oC.At surface x = 0, the temperature was suddenly increased to 100 oC.What is the time taken for x = 45 cm to reach 50oC? Material is Gold and ? =127 x 10^-6 m^2/s you need to find the time =? You need to use Matlab to solve 1.Find the time of heat transfer based on the given information 2.What are boundary conditions? 3.Plot a graph demonstrating the temperature profile of depth (or distance) with time You need to solve for the Gold material only The instructor upload a video for the programing and we made the code but he said we have to add a few thing about 2 coding line and we must find the time from the graph , not from the equations . I will upload the question and our coding . If you could check our code and try to resolve it

Running head: Physics
PHYSICS
Name of the Student
Name of the University
Author Note

1PHYSICS
MATLAB code:
L = 0.45; %wall thickness
n = 10; %number of simulation nodes
T0 = 0; %deg C, initial temperature of wall
T1s = 100; %deg C, surface 1 temperature
Tx = 50; %deg C, distance x temperature
dx = L/n; %m, node thickness
alpha = 127*10^-6; %thermal diffusivity
t_final = 63; %s, simulation time
dt= 0.1; %s, fixed time step
x = 0:dx:L-dx/2;
T = ones(n,1)*T0;

2PHYSICS
dTdt = zeros(n,1);
t = 0:dt:t_final;
time = t(1);
for j = 1:length(t)
for i = 2:n-1
dTdt(i) = alpha*(-(T(i)-T(i-1))/dx^2+(T(i+1)-T(i))/dx^2);
end
dTdt(1)= alpha*(-(T(1)-T1s)/dx^2+(T(2)-T(1))/dx^2);
dTdt(n)= alpha*(-(T(n)-T(n-1))/dx^2+(Tx-T(n))/dx^2);
T = T+dTdt*dt;
if(x==0.45)AND(T==50)
Td=T;
break
end
figure(1)
plot(x,T, 'Linewidth', 3)
axis([0 L 0 50])
xlabel('Distance (m)')
ylabel('Temperature (\circC)')

3PHYSICS
pause(0.001)
time = t(1) + dt;
end
fprintf('time taken for x=45 cm to reach 50 degree C is %d sec \n',time)
Output:
time taken for x=45 cm to reach 50 degree C is 63 sec
Temperature with distance graph:
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45
Distance (m)
0
5
10
15
20
25
30
35
40
45
50
Temperature ( °C)

4PHYSICS
Boundary conditions:
Initial temperature is 0 degree C.
So, T(0) = 0 C for all x
At x= 0 T(0) = 100 degree C. (as temperature suddenly increased to 100 degree C)
Tend = 45 degree C.