Resistance and Heat transfer

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Created by
sarah

Cards (13)

  • Resistance
    • Resistance is how difficult it is for current to flow
    • The higher the resistance, the more difficult for the current to flow
    • Low resistance makes it easier for current to flow
  • Factors contributing to how much resistance wires in a circuit has
    1. Length
    2. Width
    3. Material
  • Every time electrons travel through a region with resistance, they lose a little bit of energy. This results in a loss of energy as the current flows through a circuit component. This energy loss is known as a voltage drop.
  • A component with a high resistance has a large voltage drop. This means that it uses lots of energy.
  • There is a small voltage drop across a component with a low resistance. This component loses less energy than a component with high resistance.
  • Sometimes it is difficult for a current to flow through a circuit component. This is due to the resistance of the circuit component. Resistance is how much a component opposes the flow of current through it.
  • Electrons travelling around a circuit will encounter resistance. Resistance has the unit ohm (Ω). It was named after the important physicist Georg Ohm.
  • If a component has high resistance it has more ohms, if it has low resistance, it has less ohms.
  • Length
    The longer the wire, the more resistance (further distance electrons have to travel). Double length = double resistance. It has more resistance because the electrons need to travel further and will lose more energy.
  • Width
    The wider the wire, the more electrons can fit through, less energy is lost. In a thinner wire, it is harder for electrons to move around atoms but in a thick wire it is easier for them to move around
  • Material
    Metal wire has lower resistance than plastic (plastic is a conductor that prevents the flow of electrons)
  • Ohm’s law states that the potential difference across a component is directly proportional to the current passing through it when its temperature remains constant.
  • Resistance is measured using an ammeter and voltmeter connected together. The voltage across the resistor is measured by the voltmeter and the current flowing through the resistor is measured by the ammeter.