# Science: Electricity

 The flashcards below were created by user nzsurfer on FreezingBlue Flashcards. Why does it not matter where an ammeter is placed in a series circuit? It does not matter where an ammeter is placed in a series circuit because the current is the same, everywhere. How will the number of lightbulbs in a series circuit affect the current? A series circuit with more lightbulbs will have less current than a circuit with less lightbulbs as the flow of electrons has been slowed down. Does it matter where you place the ammeter (A)? Yes Does the current travel around evenly in one path in a parallel circuit like it does in a series circuit? No it doesn't. This is because there are alternative pathways for the current to travel. Electricity is a convenient type of energy as it travels rapidly along a conducting pathway. What can electrical energy be changed into? Electrical energy can be changed into: sound energy (radio speakers), heat energy (hair straightener), light energy (lightbulb) and kinetic energy (microwave). What is a conductor? A conductor is a material that allows electrons to flow. What is a non-conductor called? An insulator. What is an insulator? A material that doesn't allow electrons to flow. How does an insulator work? An insulator stops electricity from escaping to the ground. The electrons are held tightly to the positive charges and because of this the electrons are unable to move. Anything that has a lot of air is an insulator. E.g. paper, wood, rubber. How does a conductor work? The electrons in a conductor are not strongly attracted to a particular nucleus or the positive charges, meaning that the electrons can move freely and easily. All metals are conductors. E.g. carbon, acids, silver. What is a fuse? A fuse is a safety device that is built into a circuit. It is a thin wire that is surrounded by an insulator. How does a fuse protect dangers? If current in a circuit gets too great; wires in the circuit can heat up (due to friction) and cause a fire, or give an electric shock. The thin wire in a fuse is designed to melt when current reaches a certain level. E.g. 5A. This breaks the circuit, meaning that the current can no longer flow. What is resistance? Resistance is the opposition to the flow of electrons through a substance. What is a resistor? A resistor is an object which opposes the flow of current. It is a component which is designed to limit the currents flow. How does resistance affect current? Lamps and resistors give resistance. If they are built into a circuit, the size of the current depends on their resistance. If in a parallel circuit, and there is more than one resistor on one pathway and only one on the other, the pathway with the least resistance receives more current than the other. However, if both pathways have equal resistance, then the current is shared equally between the two pathways. How many electrons return to the power supply per second? The number of electrons that return to the power supply per second is the same as the number leaving the power supply. How does the current in a series circuit differ to that of a current in a parallel circuit? A current is a flow of electrons. The current in a series circuit is the same all the way around. So, if you were to place an ammeter (A) in the circuit, its position would not matter, as the whole way around the circuit, the reading would be the same.However, in a parallel circuit there are alternative pathways for the current to travel. So, if you were to put an ammeter (A) in the circuit, it's position would matter, as one ammeter could be reading the current from both pathways, or just of one. The current in a parallel circuit does however add to be equal to the current leaving the power supply. What is resistance measured in, and give an example of a resistor? Resistance is measured in OHMS (Greek Letter Omega Sign). Anything that controls how hot or how loud etc, something is, is a resistor. For example: dials on oven element, light dimmer, volume control on a TV remote. Authornzsurfer ID46412 Card SetScience: Electricity DescriptionCircuits Updated2010-11-01T05:26:51Z Show Answers