PHYSICS 3RDQ

• Objects become electrically charged either by gaining or losing electrons.
• QUEEN ELIZABETH I OF ENGLAND - Found out that many other substances possess the same ability as that of AMBER
• Every object acquires this ability to attract small pieces of matter after being rubbed against another object
• ELECTROSTATICS - study all phenomena associated with electric charges at rest.
• Electric charge represented as q
• Unit for charge is coulomb (C)
• Conductivity is the measure of the ease at which an electric charge moves through a material.
• Insulators are materials that do not allow electricity to pass easily through them, while conductors are materials that allow electricity to flow freely through them.
• Conductors - Have plenty of electrons that can easily move in the materials.
• Insulators - materials that resist the flow of charges.
• Semiconductors - Intermediate between conductors and insulators
• Semiconductors conductivity is low in its pure form.
• doping - refers to atoms of different elements in very small amounts added to pure semiconductors to improve conductivity.
• N-type doping - adding donor impurity (donates electron) to increase number of free electrons in semiconductor.
• Superconductors - Only work at temperatures close to absolute zero
• Superconductors - The highest known critical temperature of a superconducting material is 203 K (-70 degree C): hydrogen sulfide
• Objects becomes electrically charged either by gaining or losing electrons
• Induced Charges - Neutral atom
• Induced Charges - Atom may gain or lose electrons
• Electron Affinity is a measure of the attraction of an atom to an electron
• Materials with higher electron affinity are capable of gaining electrons from those of lower electron affinity
• Triboelectric Series is arranged in the order of increasing electron affinity from top to bottom
• In Triboelectric Series, one that is higher on the list will become positively charged
• Charging by Conduction - Requires physical contact between a charging body and a neutral body
• Charging by Conduction - Requires physical contact between a charging body and a neutral body
• Neutral body becomes negatively charged when charged by a negatively charged body
• Neutral body becomes positively charged when charged by a positively charged body
• Charging by Induction - Body may be charged without physical contact with a charged body
• Polarization happens when negative charges on the neutral body are attracted toward the charging body if the latter is positive
• The neutral body is then grounded either by touching it or using a wire
• Charges can neither be created nor destroyed, it only transferred from one body to another
• Coulomb’s Law - Discovered that the magnitude of the electrical force between two charged particles
• Electrical force is directly proportional to the product of the magnitudes of the charges and inversely proportional to the square of the distance between them
• Objects becomes electrically charged either by gaining or losing electrons
• Electric Charge (q) Exert a force on the other charged objects even though they are at some distance away.
• Space surrounding a charged body, causes any charged particle placed in it experience an electric

  force
• Michael Faraday - Introduced the use of electric field lines of force to map out electric field
• Isolated positive charge - Electric field lines directed outward
• Isolated negative charge - Electric field lines directed inward
• Electric Field Lines - Michael Faraday