Does the length of wire in a circuit affect the resistance? Plan The aim of this investigation is to find out whether the resistance increases or decreases

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Does the length of wire in a circuit affect the resistance?

Plan

The aim of this investigation is to find out whether the resistance increases or decreases as the length of wire increases. The key factor that I plan to investigate is the length of wire, and I will alter the lengths of wire, and measure the resistance during the investigation using an ammeter and a voltmeter.

The diagram above shows wire in a circuit. The current is hitting the wire particles, which slow the current down.

I predict that the longer the wire, the higher the resistance and the lower the current.

The reason for this prediction is that when the current goes through a wire, the current hits the particles of the wire, which slow it down over a longer period of time. The path of an electron is not just a simple direct route from negative to positive, but an electron has a zigzag path, as electrons constantly collide with particles of wire. So the more collisions there are, the more friction there is, acting as the opposite force, and therefore slowing the current down. If we have a longer wire, we are forcing the current to go through a wire-full of particles for longer; therefore the current will slow down after hitting more particles inside the wire. Ohms law states that the higher the temperature, the higher the resistance. As the friction increases heat, the atoms in the material start to vibrate more, as in the kinetic theory, an increase in temperature causes the particles to obtain more energy, and that energy is transferred into movement. After taking into account all the above scientific information, I believe and predict that the longer the wire will be, the higher the friction0, the higher the resistance and the lower the current.

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To guarantee the best results I will use equipment that is quite accurate and simple to collect results from. I am going to use an ammeter and a voltmeter, and from the results given by them I will calculate the resistance using this simple formula:

Resistance = Voltage

 

                Current

The equipment I need for this experiment is:

  • Voltmeter,
  • Ammeter,
  • Power pack,
  • Metre rule,
  • Conducting wires,
  • Crocodile clips,
  • Calculator.

I will attach a section of wire on a meter rule, using sticky-tape at two end ...

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