faradays law of magentic induction

[bigjoe]

I am just confused with the discussion on this site regarding the induced emf on a generator: http://www.upscale.utoronto.ca/IYearLab/faraday.pdf

What does the article mean regading the angle theta (Θ), I am confused with the statement:
"theta (Θ) is the angle between the normal to the rotating
coil and the direction of the magnetic field".

The plane of the coil is the hollow part right?, when the coil is on a vertical position? I am just confused with the term "normal"

also the area of the coil is the area cutting the magnetic flux right?

 

[DugalMc]

Yes, the area of the coil is the hollow part , also the plane of the coil, so it has a normal, a perpendicular to that area.
When the coil rotates, the area that the magnetic field crosses changes, so the flux changes.