Electromagnetism

• The strength of a magnetic field decreases with distance from the source.
• Magnetic fields can be represented using field lines or vectors.
• A current-carrying wire produces a magnetic field around it, with the direction determined by the right hand rule (thumb points in the direction of the current, fingers curl around the wire).
• The strength of a magnetic field can be indicated by the density of the field lines.
• Magnetic field lines never cross or intersect.
• Magnetic field lines are imaginary lines that surround a magnetic field and indicate the direction of the field at any point.
• The magnetic field lines are perpendicular to the direction of motion.
• The strength of a magnetic field is determined by the density of the magnetic field lines, with a higher density indicating a stronger magnetic field and a lower density indicating a weaker magnetic field.
• Magnetic fields are created by moving charges or current-carrying wires.
• Field lines are imaginary lines that show the direction and intensity of a magnetic field, with closer lines indicating stronger fields.
• Vectors represent the magnitude and direction of a force at any point in space.
• A compass needle is used to measure the direction of a magnetic field by aligning it along the field lines.
• Electric charges moving through a conductor produce a magnetic field that is perpendicular to both the motion of the charge and the direction of the electric field.
• When two parallel wires carry equal currents in opposite directions, they attract each other due to their magnetic fields.
• Moving charged particles create a magnetic field, which can interact with other magnets or magnetic materials.
• Field lines are perpendicular to the surface where they enter/exit.
• Field lines are always perpendicular to the surface where they enter/exit.
• Electric charges produce electric fields that exert forces on other charged objects.
• Field lines always start on north poles and end on south poles.
• Stronger magnets have more tightly packed field lines.
• If the charge is positive, the force will always act towards the left side of the diagram.
• In a uniform magnetic field, the force acting on a charged particle is constant and parallel to the magnetic field lines.
• Electrically charged particles create their own magnetic field around them.
• A compass needle aligns itself along the direction of the magnetic field due to its own small magnetization.
• When a bar magnet is suspended freely, it aligns itself along a North-South axis due to Earth's magnetic field.
• Like poles repel each other while unlike poles attract each other.
• The magnetic field lines are denser near the poles of the magnet and become less dense as distance increases.
• The magnetic field lines always form closed loops, starting from one end of the magnet and returning back to where they started.
• The direction of the magnetic field is represented by the direction of the arrow on the magnetic field line.
• A vector can be represented as an arrow pointing in the direction of the force and having a length proportional to its magnitude.
• Electric charge can be positive (+) or negative (-).
• Charge is conserved - it cannot be created or destroyed, only transferred from one object to another.
• Moving charges create a magnetic field around them due to their velocity.
• Current flowing through a wire creates a magnetic field around it.
• The right hand rule can be used to determine the direction of the magnetic field produced by a current carrying wire.
• The magnetic field produced by the coil strengthens when the current increases and weakens when the current decreases.
• An electromagnet can be made by wrapping a coil around an iron core and passing a current through it.
• When the current flows through the coil, the magnetic field lines are concentrated at the centre of the coil, creating a strong magnetic field that attracts nearby ferrous objects.
• Magnetic fields have lines of force that show the strength and direction of the magnetic field at any point.
• Magnetic fields are measured using a compass needle which aligns with the lines of flux (magnetic field lines).