Electricity Review
- Electric force is the attraction or repulsion between electric charges
- Two types of charges: positive and negative
- Charging by friction – is the transfer of electrons from one uncharged object to another object by rubbing
- Charging by conduction – is the transfer of electrons from a charged object to another object by direct contact
- Charging by induction – is the movement of electrons to one part of an object that is caused by the electric field of a second object
- conductors allow the charges of an electric current to move freely through them
- insulators do not allow charges to move freely through them
- voltage causes charges to move in a circuit
- an electric current will always follow the path of least resistance
- Ohm’s Law states that resistance is equal to voltage divided by current
- In a series circuit…lights will dim when another one is added and if one light goes out all the lights go out because there is only one path for the current to follow
- In a parallel circuit there is more than one path for the current to travel thus if one bulb goes out the others stay lit
- A short circuit allows the current to take the path of least resistance
- A current of greater than 0.2 amps can cause burns and stop your heart
- Electromagnetism is the interaction of magnetic and electric forces
- When an electric current is run through a wire a magnetic field is produced
- To increase the strength of an electromagnet you can: 1. use a stronger ferromagnetic core; 2. increase the number of coils; 3. increase the current; 4. wind the coils more tightly
- An electric current is used to turn the pointer of galvanometer
- An electric motor transforms electrical energy into mechanical energy
