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# Electricity- Physics

### electrical energy in the home

Question | Answer |
---|---|

The main sources of domestic energy have changed over time. | wood, domesticated animals, oil, natural gas and fossil fuels (as coal) |

Advantages of sources of energy in communities | production of light, domestic appliances, communications, entertainment, remotes areas use portable generators, and safety (i.e. secruity) |

Disadvantages of sources of energy in communities | polluted environment, society migrates to city, health (i.e. obesity through electronics), and employment given to machines |

remote locations use what for electricity?? | portable generators, wind energy, solar energy and hydropower |

how did Galvanni contribute?? | connected 2 different metals and found 'animal electricity' when legs contracted |

how did Volta contribute?? | Used 2 different metals and salt solution to create the Voltaic Pile. Created sparks and is the fore-runner of present day batteries |

how did Davy contribute?? | worked with electrochemical cells to show the reaction of metal and salt solution. |

how did Volta and Davy's work contribute?? | their contributions led to electric batteries (the 1st form of portable electricity) |

Protons and electrons?? | have the same magnitude proton = + electron = - |

1 Coulomb = ? | 6.25 x 10^18 electrons |

charge of one proton/electron? | (+ or -) 1.6 x 10^-19 C |

what is the measure of electric charges?? | Coulombs |

methods of charging??? | by friction (rubbing one object against another), by charging (in contact with another object), and by induction (no physical contact) |

Electric field strength?? | - is defined as the size of the electric force acting on a charge. - E= F/q F= size of force on charge (N), q= size of charge (C) OR E=V/d WHERE v=potential difference between 2 plates and d= distance between plates |

Current equals ??? | I= q/t I= ne/t where n=number of electrons and e=size of charge of each electron= 1.6x10^-19 C |

electric field properties?? | positive to negative |

DC & AC?? | DC- Direct current AC- Alternating current |

potential differance (voltage)? | V= W/q where w=work/electric potential energy (J) and q=magnitude of charge (C) |

conductor and resistor??? | conductor= low resistance resistor= high resistance |

Ohm's law?? | V=IR |

conventional current?? | theoretical flow of positive charges from = to - terminal at a power source |

electron current?? | actual flow of negative charges from - to + terminal |

resistance factor equation | R= nature*(length/c.s area) |

Qualitatively describe how length affects the movement of electricity in a conductor | length is directly proportional to resistance i.e. the longer the wire, the higher the resistance! |

Qualitatively describe how cross-sectional area affects the movement of electricity in a conductor | the resistance is inversely proportional to its area of cross section i.e. thin wire has a large resistance |

Qualitatively describe how temperature affects the movement of electricity in a conductor | the resistance of a conductor is directly proportional to temperature i.e. resistance of a light globe will increase as it gets hotter |

Qualitatively describe how material affects the movement of electricity in a conductor | depends on the material. this is determined by a numerical value called resistivity (denoted by rho) i.e. high resistivity = high resistance |

how many paths in a series circuit? | one path |

how many paths in a parallel circuit? | multiple paths |

what is equal and needs to be added in a series circuit?? | only current in series circuit is equal. Resistance and voltage needs to be added. |

what is equal and needs to be added in a parallel circuit?? | only voltage is equal. Current and the reciporical of resistance needs to be added. |

describe an ammeter. | measures current in a circuit. connects in series. has low resistance. |

describe a voltmeter. | measures potential difference betwen 2 points in a circuit. connects in parallel. has high resistance. |

power is what?? |