Electrical Energy

• A magnetic field is a region in which a ferromagnetic metal or charged particle experiences a force. Symbol B. Unit Tesla (T)
• Magnetic field lines NEVER cross
• Field lines always run from NORTH to SOUTH (N to S)
• Regions where fields lines are closer together indicate a stronger magnetic field.
• Region between two different poles is considered uniform (parallel) and equidistant (equal strength).
• Region between two same poles contain no magnetic force (Fnet = 0N) as the field cancels out.
• NORTH geographic Earth is the south magnetic pole AND SOUTH geographic pole is the magnetic north pole.
• Electrical current flowing through a conducting wire causes a magnetic field to form.
• x = into the page
• . = out of the page
• A solenoid is a coil of wire that produces a strong uniform magnetic field when it carries an electric current.
• Same directed current electrical poles are attracted to each other.
• If two poles run together in the same direction they create a bigger current together. (merge)
• For electrical wires with a magnetic field it is flowing in a circular pattern.
• Inside a solenoid the magnetic field is from SOUTH to NORTH
• Solenoid: The magnetic field from each of the wires combines to produce a field similar to a bar magnet.
• Solenoid: The right-hand grip rule can be used to find the direction of the NORTH pole of the solenoid.
• Calculating Magnetic field strength: B = kI/d
• B = magnetic field strength (Tesla: T)
• k = Magnetic force constant 2 x 10^-7 (TmA^-1)
• d = distance from the wire (m)
• I = Current (A)
• AC: definition

  Alternating Current is when the direction of the current is constantly swapping back and forth. This is when we use an alternating potential difference (voltage).
• What direction does current flow in AC?

  The alternating flow of current switches direction.
• DC: definition

  Direct Current
• What direction does the current flow in DC?

  From negative to positive
• AC examples

  Power lines
• DC examples

  Modern electrical devices (phones, etc)
• The voltage that is electricity supplied at in New Zealand 240 volts (50Hz)
• How is AC voltage induced by moving a coiled wire through a magnetic field?

  Moving wire through a magnetic field which causes/induces EMF (electromotive force).
• How is AC current induced?

  Moving wire through a magnetic field which causes/induces EMF. Once connected to a circuit, it will apply its EMF to induce a current.
• Kinetic Energy + Magnetic Field --> Electricity
• Magnetic Field + electricity --> Kinetic energy
• Inserting a magnetic pole into a solenoid will always repel due to the poles being alike.
• Moving another solenoid together they will repel as they both have south meeting each other.
• Increase EMF and P.D.

  1. Increase the number of coils (change P.D.)
  2. Increase speed of motion
  3. Use Soft Iron core for circuits
• The use of transformers will allow the voltage to "step up" or "step down"
• Primary Power = Secondary Power
• No matter if the voltage steps up/down, POWER will be the same. Current will just change to make sure they both are the same power
• Uranium is used in nuclear fission reactions to generate heat energy in a reactor