Calculating the direction of Earth's magnetic field

[SnapDragon]

Please help! Calculating the direction of Earth's magnetic field

Homework Statement

Calculate the direction of Earth's magnetic field.

Homework Equations

The Attempt at a Solution

3 components of the magnetic field:

Geographic South to North: 0.01670 mT
Geographic West to East: 0.002147 mT
Up to down (up is the sky, down is the ground): 0.03722 mT

Calculating angle East of North:

tanθ=0.002147/0.01670
θ=7.33° East of North

Angle below horizontal:

tanθ=0.03722/√(0.01670²+0.002147²)
θ=65.66° below horizontal

Is my attempt correct?

 

[SnapDragon]

If I did the first question correctly, I need help with this question:

Compare the direction of the projection of this magnetic field vector on the horizontal
plane (the angle to the east (or west) of geographic north) with the direction of the
compass.

I honestly don't understand what they're asking here. Are they saying to compare 7.33° with the direction of the compass? How do I find the direction of the compass?

 

[SnapDragon]

Also, one last question:

The magnetic field in anywhere between two helmholtz coils is uniform, right?

 

[SnapDragon]

Anybody? This is due tomorrow. :|

 

[haruspex]

If I did the first question correctly, I need help with this question:

Compare the direction of the projection of this magnetic field vector on the horizontal
plane (the angle to the east (or west) of geographic north) with the direction of the
compass.

I honestly don't understand what they're asking here. Are they saying to compare 7.33° with the direction of the compass? How do I find the direction of the compass?

Your answer looks fine. I am similarly bemused by the second question. Since it says "the compass", I would expect it to be in the context of some actual compass described or supplied elsewhere.

 

[SnapDragon]

Your answer looks fine. I am similarly bemused by the second question. Since it says "the compass", I would expect it to be in the context of some actual compass described or supplied elsewhere.

Maybe they're asking to check the percent error compared to the real value?

 

[haruspex]

Maybe they're asking to check the percent error compared to the real value?

It's not a percent error.
By 'real' value, do you mean true north, or the known declination for where you are?

 

[SnapDragon]

This is the lab btw: http://www.physics.ryerson.ca/sites/default/files/u3/2011/06/MagnFieldWVernierJC.pdf

 

[SnapDragon]

It's not a percent error.
By 'real' value, do you mean true north, or the known declination for where you are?

I have no idea.

Don't worry about it. I'm just going to hand in what I have. No point stressing over it since no other students seem to know the answers either.

 

[haruspex]

When you fill in the data table for e.g. the NS field, how are you determining that it's NS? Do you use the compass for that? If so, are you taking it from the magnetic N according to the compass, or are you correcting for declination?

 

[SnapDragon]

When you fill in the data table for e.g. the NS field, how are you determining that it's NS? Do you use the compass for that?

Yes.

If so, are you taking it from the magnetic N according to the compass, or are you correcting for declination?

I am taking it from the magnetic N according to the compass.