1. Ch. 21 - Electricity II. Electric Current  Cell and Battery  Potential Difference  Current  Resistance  Ohm’s Law

2. A. Cell and Battery  Cell  a device that produces an electric current by converting chemical energy into electrical energy  A cell conducts a current  Battery  made up of many cells and also converts chemical energy into electrical energy

3. C. Current  Current  flow of electrons through a conductor  depends on # of electrons passing a point in a given time  measured in amperes (A)

4. D. Resistance  Resistance  opposition to the flow of electrons  electrical energy is converted to thermal energy & light  measured in ohms (  ) Copper - low resistance Tungsten - high resistance

5. D. Resistance  Resistance depends on…  the conductor good conductors have low resistance  wire thickness less resistance in thicker wires  wire length less resistance in shorter wires  temp - less resistance at low temps