The document discusses the variation of magnetic field in a circular coil. It explains that a magnetic coil is a conductor such as a wire wound into a spiral shape. When electric current passes through the coil, it generates a circular magnetic field around the conductor according to Ampere's law. The magnetic field intensity is highest at the center of the coil and decreases as the distance from the center increases. A graph of tangent angle versus distance from the coil center shows the magnetic field starts concave then becomes convex, with points of inflection at the coil radius.

1. VARIATION OF MAGNETIC FIELD
IN A CIRCULAR COIL

2. WHAT IS A MAGNETIC FIELD
• A magnetic field is the physical phenomenon produced by
moving electric charges and exhibited by ferrous materials.
• A magnetic field is a vector field that describes the magnetic
influence of electric charges in relative motion and magnetized
materials. Magnetic fields are observed in a wide range of size
scales, from subatomic particles to galaxies.
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3. WHAT IS A MAGNETIC COIL?
• An electromagnetic coil is an electrical conductor such as a wire in the shape of a
coil, spiral or helix.
• Electromagnetic coils are used in electrical engineering, in applications where
electric currents interact with magnetic fields, in devices such as electric motors,
generators, electromagnets, transformers, . Either an electric current is passed
through the wire of the coil to generate a magnetic field, or conversely an external
time-varying magnetic field through the interior of the coil generates an EMF
(voltage) in the conductor.
• A current through any conductor creates a circular magnetic field around the
conductor due to Ampere's law.
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4. MAIN THINGS TO REMEMBER:
To study the variation of magnetic field in a circular coil. we
should now about the tangent law and also the direction and
magnitude of the magnetic field around the coil.
Tangent law: it is a way to compare the strengths of two magnets
fields that are perpendicular to each other.

5. THINGS I HAVE STUDIED:
• The intensity of magnetic field is maximum at the center
• And it goes on decreasing as we move away from the center of
the coil toward right or left
• The distance between the two points of inflexion is equal to the
radius of coil is equal to the radius of the circle.

6. • We will get a graph between tan angle and x where the tan
angle is the deflection produced in a deflection magnetometer
and x is the distance from the center of the coil.
• The curve is first concave towards o and then afterwards
become convex.
• The points where the curve changes its nature is called the
points of inflection

7. THE GRAPH