Homework Help: Magnetic flux

cerium · Mar 15, 2010

1. The problem statement, all variables and given/known data

if a questions states that the angle of 66 degrees is below the horizontal is that the angle I put into the equation

2. Relevant equations

3. The attempt at a solution

tiny-tim · Mar 15, 2010

Hi cerium!

cerium said: ↑

if a questions states that the angle of 66 degrees is below the horizontal is that the angle I put into the equation

erm … what equation?

cerium · Mar 15, 2010

Sorry missed out the most important part
ABcos(theata) cant find symbol for that.
the question asked you to find magnetic flux I have worked out A and B but Im unsure what it means when it says : the angle is 66 degrees below the horizontal:
Thanks

tiny-tim · Mar 15, 2010

Hi cerium!

(have a theta: θ and a degree: º )

(i still don't understand what this is about )

I assume that θ is the angle between A and B,

so what are A and B?

cerium · Mar 15, 2010

The earths magnetic field at a certian location in the uk has a magnitude of 48x10-6T and is directed at 66 degrees below the horizontal.
Determine the magnitude of flux of the earths magnetic field through a wedding ring of diameter 2.2cm when the ring is held in the horizontal plane.
What is the magnitude of flux change when the ring is flipped through 180 degrees.

It the angle that is bothering me
Thanks

tiny-tim · Mar 15, 2010

ah!

so B is 66º below the horizontal.

ok, the flux through a surface (or through its boundary) is greatest when the surface is perpendicular to the field, ie when the normal to the surface is parallel to the field.

So θ is the angle between B and the normal to the ring.

cerium · Mar 15, 2010

I see so I would be using cos24 not cos66

tiny-tim · Mar 15, 2010

Yes.