Study Guide Electricity Magnetism Answers 1x274f

Study Guide: Electricity & Magnetism- ANSWERS 1. Study all vocab:                  

electric force: attractive or repulsive interaction between any two charged objects electric field: radially outward from a positive charge; radially in toward a negative point charge conduction: flow of charge carriers in response to an electric field in a conductor; charging by conduction transfer charges onto an uncharged object by bringing it into direct induction: an object carrying a varying current causes another current to flow; the happens because any object carrying a current has a magnetic field formed around it friction: When one surface or object rubs against another conservation of charge: the total electric charge in an isolated system never changes static electricity: a stationary (nonmoving) electric charge, usually made by friction, that causes sparks or crackling and the attraction of dust or hair electric current: the flow of an electric charge ampere (amp): a unit of electric current voltage: a electromotive (moving electricity) force expressed in volts resistance: an electrical quantity that measures how the device of material reduces the electric flow through it. Circuit: a route that electricity takes; movement starts and finishes in the same place series circuit: a closed circuit in which the current follows one path parallel circuit: a circuit that is divided into two or more paths magnet: a piece of iron (or something that contains iron) that exhibits properties of magnetism (attracts other iron-containing objects; has an external magnetic field magnetic poles: each end of a magnet; south pole (magnetic induction come together) and north pole (magnetic induction split apart) magnetic force: one of four forces in nature; whenever objects interact in which there is a charge in motion magnetic field: a region around a magnetic material or a moving electrical charge within which the force of magnetism acts.

2. Understand: charges of the subatomic particles (electrons-negative, protons- positive) and how they behave (electrons have a spin that gives them momentum which causes them to carry a magnetic force) 3. Know the 3 ways that objects can be charged 1. Friction 2. Conduction 3. Induction 4. Know the difference between conductors & insulators: 1. Conductors conduct electrical current easily. Ex: copper, aluminum, gold, silver 2. Insulators oppose electrical current. Ex: glass, air, plastic, rubber, wood

5. Know the difference between current electricity & static electricity 1. Static electricity occurs when there is an imbalance of positively and negatively charged atoms; current electricity is a constant flow of electrons 6. Identify the parts of a circuit 1. Power source: either electrical or batter; provides power to the load 2. Load: device using the electricity such as computer, light bulb, etc. 3. Conducting path: the wires that carry the power from the power source to the load 7. Identify types of circuits & the advantages & disadvantages of each : 



series circuits: o Disadvantages: if one component in a series circuit fails, then all the components fail because the circuit has been broken; the more components there are, the greater the resistance o Advantages: do not overheat easily; easy to learn and make; the more power devices, the higher the output in volts; every component carry the same current parallel circuits: o Disadvantages: requires a lot of wires; cannot increase or multiple the voltage in a parallel circuit o Advantages: failure of one component does not lead to the failure of other components; more components can be added without the need for more voltage

8. Know what is produced from an electric current: magnetic field 9. Know about electromagnets: 1. how they are made- when an electric current flows in a wire and you wrap the wire into a coil 2. what makes them stronger- when you add more coils you increase your current 10. Know about magnets: 1. where are the strongest parts of a magnets: at its poles 2. what happens when a magnet is cut in half: it still has a north and a south pole; maintains its magnetism 3. Earth is a magnet: magnetic field is generated by the electric currents in the conductive material of its core, created by the convection currents due to heat escaping from the core 11. Understand the relationship between electricity & magnetism 1. This is actually called electromagnetism; changing magnetic field produces an electric current in a wire or conductor 12. Explain what lightning is 1. A natural electrical discharge of a very short duration; produces a high voltage between a cloud and the ground or within a cloud 16. Ohm’s Law: calculations (I will give you the formula); relationship between resistance & current; relationship between voltage & current; relationship between resistance & voltage Increase resistance, decrease current; increase voltage, increase current; resistance does not change voltage