Electric Charges Types and Sources of Electric Charge Two kinds of electric charge – positive negative electrons protons Bohr Model of Atom Quantum Mechanical Model Materials with equal numbers of neg. and pos. charge are said to be electrically neutral.

Electric Charges Types and Sources of Electric Charge THANKS BEN! Ben Franklin actually did a great deal of experimentation in the area of electricity. However, Ben Franklin worked on the negative and Positive charges a lot. which we are using till now.

Electric Charges Properties of Electric Charge Charge is quantized. Positive and Negative charges have same magnitude e = p = 1.6 x C SI unit of charge is the Coulomb Charge is conserved. only charge will be transferred, but can not be destroyed or made.

Electric Charges Atoms and Materials Classification of Materials – Conductors, Insulators, Semiconductors Conductors Electrons are free to move about the material Insulators Electrons are bound to the atoms - can’t move (conduct). Different elements will have different types of bonds – different strengths.

Electric Charges Insulators Free Standing Atoms are randomly oriented Charge does not actually move In/on the insulator – redistributes. Polarizes the material.

Electric Current

THE ELECTRIC BATTERY A BATTERY is a source of electric energy. A simple battery contains two dissimilar metals, called ELECTRODES, and a solution called the ELECTROLYTE, in which the electrodes are partially immersed.

ELECTRIC CURRENT AnAn electric CURRENT exists whenever electric charge flows through a region, e.g., a simple light bulb circuit. The magnitude of the current is measured in AMPERES (Amps/A), where 1 ampere = 1coulomb/second I = q / t.

CONVENTIONAL CURRENT vs ELECTRON CURRENT TheThe direction of CONVENTIONAL CURRENT is in the direction in which positive charge flows. In gases and liquids both positive and negative ions move. Only negative charges, i.e., electrons, move through solids and this is referred to as ELECTRON CURRENT. For historical reasons, conventional current is used in referring to the direction of electric charge flow.

OHM'S LAW OHM'S LAW The magnitude of the electric current that flows through a closed circuit depends directly on the voltage between the battery terminals and inversely to the circuit resistance. The relationship that connects current, voltage and resistance is known as OHM'S LAW and is written as follows: I = V/R or V = IR T The current is measured in amperes, the voltage in volts and the resistance in ohms ().

Resistors 4 Symbol on a schematic diagram For the color code, the first two colors represent the first two digits in the value of the resistor, the third represents the power of ten that it must be multiplied by, and the fourth is the tolerance.

RESISTIVITY 4 RESISTIVITY: When electric charge flows through a circuit it encounters electrical RESISTANCE. The resistance of a metal conductor or this opposition property of a conductor is called as resistivity.

ELECTRIC POWER 4 The rate at which work is done to maintain an electric current in a circuit is termed ELECTRIC POWER. 4 W = QV. 4 Work is required to transfer charge through an electric circuit. The work required depends on the amount of charge transferred through the circuit and the potential difference between the terminals of the battery: