Question

α = 0.0007889 T, I = 2.9 A

Other Magnetic Fields: First, based on your value for α and a typical value from your data for I in this experiment, compute B_HH, the magnetic field of your Helmholtz Coil. Then, compare it to...

• Earth's field: The horizontal component of the Earth's magnetic field is about 20μT. We avoided this impacting our experiment by orienting our machine correctly. Based on how this field compares to the field of our Helmholtz coil, is that a necessary course of action, do you think?
• Other coils: The coils don't only have magnetic fields inside; they make magnetic fields at some distance, too. Consider the magnetic field of the people across the table from you, and consider their coil as a magnetic dipole some distance away. First, compute the magnetic moment of it, based on the current, number of turns and (an estimate of) area. Then, using that magnetic moment, an estimate of how far apart your coil was from theirs, and the formula for the magnetic field of a magnetic dipole, get an order-of-magnitude estimate for the magnetic field that their wires caused at the center of your coil (as a "cross-talk" effect). Is this large enough to be concerned over in this experiment?

Answer 1

(a)

Let, BHH be the magnetic field of the Helmholtz coils. Inside the pair of coils it is highly uniform and is proportional to the current I through either of the coils:

where, we know

Let us assume value of N=100 turns and R=1000 mm

then, using this we find

Based on comparison of to Earth's magnetic field, magnetic field of the coil is high enough to be not affected by the magentic field of the Earth. Hence, it was not a necessary course of action.  

(b)

magnetic moment of a solenoid is given as

Where N is the number of turns -100,the current I =2.9 A, the cross sectional area S = 4**(1500mm)^2

Considering the second coil as the magnetic dipole the magnetic field generated by it at the distance r= 10m (i.e. we consider the distance between the coils to be 10 m) is,

As we have considered both the coils as dipoles, is the angle between their axes. Let it be 00.

Then we get

it is of the order of 10-9, hence it is not to be concerned about.