1. CHAPTER 2 PHYSICS FOR JUNIOR HIGH SCHOOL IX

2. CLOSED ELECTRICAL CIRCUIT  Closed electrical circuit is electric current in a circuit that can only flow in closed circuit.

3. PHYSICS FOR JUNIOR HIGH SCHOOL IX CLOSED ELECTRICAL CIRCUIT a.The connectivity between current, potential difference, and resistance. To see how they influence each other, George Simone Ohm (1789–1854) researched the connectivity between electrical potential (V), current (I), and Resistance (R). Mathematically, it can be stated as follows : b.Specific resistance Resistance value of one medium depends on the following factors :  Wire length, the longer the wire, the bigger the resistance.  Wire surface-are, the bigger the surface-area, the smaller the resistance.  Types of substance.

4. PHYSICS FOR JUNIOR HIGH SCHOOL IX CLOSED ELECTRICAL CIRCUIT Here are some types of resistor in electricalcircuit :  rheostat  Colored-belt resistor  Potentiometer Specicfic resistence is a special property of one substance: conductor, isolator, semiconductor  Conductor is anything that can flow electrical current well.  Isolator is anything that can’t flow electrical current.  Semiconductor is anything whose property between conductor and isolator.

6. PHYSICS FOR JUNIOR HIGH SCHOOL IX CLOSED ELECTRICAL CIRCUIT CLOSED ELECTRICAL CIRCUIT d.Ohm laws in closed electrical circuit  Current in that circuit can be counted by Ohm laws

7. PHYSICS FOR JUNIOR HIGH SCHOOL IX OPEN ELECTRICAL CIRCUIT B.OPEN CIRCUIT Open circuit is the contrary of closed circuit, in this circuit, there’s no any voltage difference. So that no electron movement that causes no electrical current. In this circuit, electron can not move to positive pole of voltage source, because it should not connect each other (disturbed). Lamp turned off Switch opened

8. PHYSICS FOR JUNIOR HIGH SCHOOL IX THANK YOU