What is diffraction patterns ? what is diffraction angles ?

The diffraction pattern is that formed when a wave is deflected when it passes through an opening or encounters an obstacle.  

When this occurs, the wave bends around the corners of the obstacle or passes through the opening of the slit that acts as an obstacle, forming multiple patterns with the shape of the aperture of the slit.

Note that the principal condition for the occurrence of this phenomena is that the obstacle must be comparable in size (similar size) to the size of the wavelength.

This means the smaller the slit or obstacle (diffracting object), the wider the resulting diffraction pattern, and the greater the obstacle, the narrower de resulting patter.

Is the output resulting angle as measured from the surface that is normal (perpendicular) to the slit.

Now, if instead of a slit we have a diffraction grating, different wavelengths of light (different colors is we talk about the visible spectrum) will pass through the grating at different angles.

answer; how far out of place which the object finished relative to the starting location;

answer(20) psi;