I don't know what's wrong in this code, it doen't produce a graph.

clear

clc

y = -4:0.01:4;%distance to fringes on the screen

Lembda=input('Enter your wavelength ')

Lambda = Lembda*1e-9; % Wavelength in m

a=input('enter the single slit width ')

a = a*1e-3; % Units to m

d=input('enter the slit width')

d = d*1e-3; % Units to m

L = 5*d;

for i = 1:length(y)

theta(i) = atan(y(i)/100/L); % Unit conversion of y to m %From the figure

alpha(i) = pi.*a.*sin(theta(i))./Lambda;

beta(i) = pi.*d.*sin(theta(i))./Lambda;

IR = (cos(beta(i)).^2).*(sin(alpha(i))./alpha(i)).^2;

end

plot(y,IR)

xlabel('y (in cm)')

ylabel('I/Imax')

title('Intensity Ratio Plot')

grid on

Answer 1

[KALYAN ACHARJYA]

IR(i)= (cos(beta(i)).^2).*(sin(alpha(i))./alpha(i)).^2;
%..^ here inside for loop