electromagnets

• resistance = potential difference / current
• potential difference (voltage) - the ammount of energy shifted from the battery to the moving charge, to circuit components, in volts (V)
• reistance - a property of a component, making it difficult for charge to pass through, in ohms
• electrical conductor - a material that allows current to flow through it easily, and has a low resistance
• electrical insulator - a material that does not allow current to flow easily, and has a high resistance
• current is a movement of eletrons and is the same everywhere in a serues circuit. current divides between loops in a parallel circuit, combines when loops meet, lights up bulbs and make components work
• around a charged object, thhe electric field affects other charged objects, causing them to be attracted or repelled. the field strength decreases with distance
• two similary charged objects repel, two differently charged objects attract
• negatively charged - an object that has gained electrons as a result of the charging process
• positively charged - an object that has lost electrons as a result of the charging process
• electrons - tiny particles which are part of atoms and carry a negative charge
• charged up - when maerials are rubbed together, electrons move from one surface to another
• electrostatic force - non contact force between two charged objects
• current - flow of electric charge, in amperes (A)
• in series - if components in a circuit are on the same loop
• in parallel - if some components are on separate loops
• field - the area where other objects feel an electrostatic force
• an electromagnet uses sthe principle that a current through a wire causes a magnetic field. its strength depends on the current, the core and the number of coils in the solenoid
• the magnetic field of an electromagnet decreases in strength with distance
• electromagnet - a non permanent magnet turned on and off by controlling the current through it
• solenoid - wire wound into a tight coil, part of an electomagnet
• core - soft iron metal which the solenoid is wrapped around