IGCSE Physics\Electromagnetism\Important Concepts
IGCSE PHYSICS
ELECTROMAGNETISM: IMPORTANT CONCEPTS
THE MAGNETIC EFFECT OF CURRENT
When current flows in a conductor, the flow of electrons in the conductor causes a
magnetic field to be created around the conductor. A magnet or magnetic material
placed near the current-carrying conductor will experience a magnetic force.
The magnetic field pattern, as well as the direction of the magnetic lines of force
can be determined by placing a plotting compass around the current-carrying
conductor, similar to the method used to construct magnetic field lines around a bar
magnet.
Representation of direction of current in a wire by drawing the cross section of the
wire:
: current into page
: current out of page
When current flows in a straight wire, the magnetic field created around the wire is
as follows:
(a) The distance between magnetic lines of force (i.e. magnetic field lines)
increases with increasing distance from the wire, indicating that the magnetic
field becomes weaker at a further distance from the wire.
(b) A larger magnitude of current flowing in the wire results in a stronger
magnetic field around the wire.
(c) The direction of the magnetic field around a wire can be determined using
(i) s screw rule)
(ii) Right hand grip rule
curren
t
field
(d) Therefore, the magnetic field pattern around a straight wire carrying current:
______________________________________________________________________________
Nakazawa EduServ. Created by Jackson Tik, B.Sc. (NUS). ©All rights reserved.
1
, IGCSE Physics\Electromagnetism\Important Concepts
Current into page: Current out of page:
When current flows in a flat coil (plane coil), the magnetic field created around the
coil is as follows:
(a) The distance between the magnetic field lines are closer in the region inside
the coil, indicating a stronger magnetic field is present inside the coil compared
to outside the coil. This is because the magnetic field lines in the region inside
the coil have the same direction and are confined in a small area.
(b) A larger magnitude of current in the coil and a greater number of turns of the
coil will result in a stronger magnetic field around the coil.
(c) Therefore, the magnetic field pattern around a flat coil carrying current:
When current flows in a solenoid, the magnetic field created around the solenoid is
as follows:
______________________________________________________________________________
Nakazawa EduServ. Created by Jackson Tik, B.Sc. (NUS). ©All rights reserved.
2
IGCSE PHYSICS
ELECTROMAGNETISM: IMPORTANT CONCEPTS
THE MAGNETIC EFFECT OF CURRENT
When current flows in a conductor, the flow of electrons in the conductor causes a
magnetic field to be created around the conductor. A magnet or magnetic material
placed near the current-carrying conductor will experience a magnetic force.
The magnetic field pattern, as well as the direction of the magnetic lines of force
can be determined by placing a plotting compass around the current-carrying
conductor, similar to the method used to construct magnetic field lines around a bar
magnet.
Representation of direction of current in a wire by drawing the cross section of the
wire:
: current into page
: current out of page
When current flows in a straight wire, the magnetic field created around the wire is
as follows:
(a) The distance between magnetic lines of force (i.e. magnetic field lines)
increases with increasing distance from the wire, indicating that the magnetic
field becomes weaker at a further distance from the wire.
(b) A larger magnitude of current flowing in the wire results in a stronger
magnetic field around the wire.
(c) The direction of the magnetic field around a wire can be determined using
(i) s screw rule)
(ii) Right hand grip rule
curren
t
field
(d) Therefore, the magnetic field pattern around a straight wire carrying current:
______________________________________________________________________________
Nakazawa EduServ. Created by Jackson Tik, B.Sc. (NUS). ©All rights reserved.
1
, IGCSE Physics\Electromagnetism\Important Concepts
Current into page: Current out of page:
When current flows in a flat coil (plane coil), the magnetic field created around the
coil is as follows:
(a) The distance between the magnetic field lines are closer in the region inside
the coil, indicating a stronger magnetic field is present inside the coil compared
to outside the coil. This is because the magnetic field lines in the region inside
the coil have the same direction and are confined in a small area.
(b) A larger magnitude of current in the coil and a greater number of turns of the
coil will result in a stronger magnetic field around the coil.
(c) Therefore, the magnetic field pattern around a flat coil carrying current:
When current flows in a solenoid, the magnetic field created around the solenoid is
as follows:
______________________________________________________________________________
Nakazawa EduServ. Created by Jackson Tik, B.Sc. (NUS). ©All rights reserved.
2
