This document discusses magnetic fields and field lines. It explains that a bar magnet will align itself with the Earth's magnetic field, with one end pointing north and the other pointing south. It defines a magnetic field as the region around a magnet or current where its influence can be detected. The document also discusses how electric current flowing through a solenoid creates a magnetic field similar to a bar magnet. Additionally, it explains that increasing current or decreasing the radius of a loop of wire carrying a current will increase the strength of the magnetic field detected by a compass.
2. Magnetic Fields and field Lines
When a bar magnet is suspended freely from
its centre by a thread, one end of the magnet
points towards the north of the earth and the
other end of the magnet points towards the
south of the earth.The end of the magnet
pointing toward north of the earth is called
north poles of the magnet.
4. Magnetic Define
The space or region around a magnet (or a
current carrying wire) within with its influence
can be felt (or magnetic force is experienced)
by another magnet is called magnetic field.
To locate the magnetic or a bar magnet , we
use iron fillings, or a magnetic compass.
5. The amount of current flow
through a solenoid
A solenoid is a coil of many turns of an
insulated copper wire closely wound in the
shape of a tight spring.When an electric
current flows through a solenoid , a magnetic
field is set up around the solenoid which is
similar to the magnetic field of bar magnet.
7. Magnetic field due to loop wire
The amount of current flowing through the
wire: If the amount of the current flowing
through the circular wire is increased, then
the deflection of the needle of the magnetic
compass placed inside the wire also
increased. On the other hand , if the amount
of current flowing through the wire is
decreased, then the deflection of the niddle
of magnetic compass. B=I
8. Current on loop wire
The radius of the circular wire :Take two
circular wire of same radii through which the
same amount of current is flowing. It is found
that the deflection of the needle of the
magnetic compass placed at the centre of the
circular wire of smaller radius is more than
that when placed at the centre of the circular
wire of the large radius. B=1/r