Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.

Normal Size Small Size show me how

Normal Size Small Size show me how

# electricity

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

A current will flow through an electrical component only if there is . . . | a VOLTAGE or POTENTIAL DIFFERENCE (p.d.) across its ends. |

The bigger the potential difference across a component . . . | The bigger the CURRENT that flows through it. |

Components resist a current flowing through them. The bigger their resistance . . . | The smaller the current produced by a particular voltage |

The p.d. across a component in a circuit is measured in . . . | VOLTS |

Voltage (p.d.) is measured using . . . | a VOLTMETER connected IN PARALLEL with the component. |

The CURRENT flowing through a component in a circuit is measured using . . . | an AMMETER connected IN SERIES with the component. |

The unit of current is . . . | the AMPERE (AMP) |

A current of 1 A is equal to a charge flowing of . . . | 1 COULOMB per SECOND |

In metals, a current is a flow of charged particles called . . . | ELECTRONS |

In a circuit, we say that Conventional Current always flows from . . . | The POSITIVE terminal of a cell, towards the NEGATIVE terminal. |

In metals, electricity is actually carried by NEGATIVELY charged electrons, which flow from . . . | the NEGATIVE terminal towards the POSITIVE terminal of a cell. |

The behaviour of a component in a circuit can best be studied by plotting . . . | a current-voltage graph. |

A resistor at constant temperature has a constant ratio of . . . | current to voltage. Its graph is a straight line. |

The current-voltage graph for a filament lamp is NOT a straight line. The reason is . . . | Resistance increases as temperature increases. |

A diode is a device which . . . | only allows a current to flow one way through it. |

When components are connected in series . . . | the SAME CURRENT flows through each component. |

The total resistance of components in series is . . . | equal to the SUM of their separate resistances. |

The total potential difference in a series circuit is . . . | shared between the individual compoents. |

If a p.d. of 12 volts is shared between two equal resistances, each one will get . . . | 6 volts. |

If a p.d. of 12 volts is shared between two resistors of 6 ohms and 12 ohms, the bigger resistor will get . . . | 8 volts. ( The smaller one gets 4 volts because it has half the resistance of the other one.) |

When components are connected IN PARALLEL . . . | There is the SAME p.d. across each component. |

The total current in a parallel circuit is equal to . . . | the SUM of the currents through each of the separate components. |

If one lamp is connected to a cell it gets a current of 1 amp. If two identical lamps are connected in parallel (to the same cell) they will get . . . | a current of 1 amp each - that makes the total current 2 amps. |

If one lamp gets a current of 1A from one cell, two lamps joined in series will get . . . | approximately half as much current ( 0.5A) because they have twice as much resistance. |

The p.d. provided by cells connected in series is equal to . . . | the SUM of the p.ds. of each cell separately bearing in mind the direction in which they are connected. |

The resistance of a component is measured inâ€¦ | OHMS |

Potential difference, current and resistance are related by Ohm's Law which statesâ€¦ | P.d. = current x resistance |

The resistance of a component is calculated by applying Ohm's law as follows: | R = Voltage / current |

If a current of 2A flows in a resistor of resistance 10 ohms, the p.d. across the resistor is . . . | 20 volts |

What is the current when a p.d. of 12v is applied across a 10 ohm resistor? | 1.2 A |

The current through a resistor at constant temperature is . . . | directly proportional to the p.d. across the resistor. |

A lamp converts electrical energy into . . . | light and heat. |

When electric charge flows through a resistor, electrical energy is transferred as . . . | HEAT |

The rate of energy transfer is called . . . | POWER |

Power is measured in watts. 1W is equal to . . . | 1 joule per second |

In an electric circuit, POWER = | P = I V |

Energy transferred = | E = P x t |

CHARGE (coulomb) = | Current x Time |

Metals are good conductors of electricity because . . . | some of their electrons can move freely throughout the metal. |

When two different materials are rubbed together . . | electrons are transferred from one to the other |

Certain materials can be used as electrical insulators. This is because . . . | they do not conduct electricity |

When a substance loses electrons, it becomes . . . | POSITIVELY charged. |

Opposite electric charges will . . . | ATTRACT each other |

Like charges . . . | REPEL each other |

A charged object can be discharged by . . . | connecting it to EARTH with a conductor |

When walking along a nylon carpet with plastic-soled shoes, you may pick up a static charge. This happens because . . . | electrons are transferred by friction from the shoes to the carpet |

When you touch a metal door handle you sometimes receive an electric shock because . . . | a charge passes from your body to earth through the door handle |

Created by:
simonpatel