Can't Join Points on a Graph

Chris Corbett (view profile)

on 4 Jan 2013

For some reason the points in the graph I am drawing don't join up, and I have no idea why. I'm sure it is probably something simple, but I don't have a clue. Can anybody see why?

Thanks, Chris.

```if true
clc;
clear all;
% Slit Width;
d = linspace(-10e-6,10e-6,500);
% Distance From Slit to Screen;
z = 0.2;
% Wavelength;
lambda = 500e-9;
% Screen;
s = linspace(-0.02,0.02,500);
% Wave Number;
k = (2.*pi)/lambda;
% Wave Number;
k = (2.*pi)/lambda;
% Width of slit;
w = (2e-6);
% Setting Value of I0
I0 = 5
```

for xs = linspace(-0.02,0.02,500);

```        xa = linspace(-10e-6,10e-6,500);
% Path Length;
r = ((((xs-xa).^2)+z.^2).^0.5);
% Electric Field;
dE = (4e-8./d).*((exp(1i.*k.*r))/r);
Etot = sum(dE);
% Etot = sum of E;
Itot = Etot.^2;
plot(xs,Itot,'-');
hold on;
end;
end```

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Image Analyst (view profile)

on 4 Jan 2013

First of all, your for loop is not in the form "for startValue : stepValue : endValue" but you probably don't even need the for loop in the first place. Secondly, Etot is a scalar while xs is a 500 element vector, so your plot() doesn't really make sense.