Creating a Uniform Magnetic Field
Located in Brookhaven National Laboratory in New York, this large Helmholtz coil is used to produce a uniform magnetic field.
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- A Helmholtz coil consists of a pair of identical circular magnetic coils that are separated by a distance equal to their radii. The magnetic field at a distance from the center of one coil is given as:
Where is the current through the coils, is the number of turns in the coil and is the radius of both of the coils. By looking at the change in the magnetic field along the -axis, it can easily be shown that this setup creates a region of nearly uniform magnetic field.
- One popular application for a Helmholtz coil is to create a region of space with a uniform magnetic field. By creating this region, scientists are able to use this method to study the magnetic properties of matter.
Using the information provided above, answer the following questions.
- If the current is increased in a Helmholtz coil, does the magnetic field change? How?
- Is the number of turns in the coils proportional or inversely proportional to the magnetic field?
- Show that at a point on the axis between the two coils, the magnetic field is given as: