Resistance of a Wire
Aim
Which factors affect the resistance of a wire?
Prediction
I believe the factors which affect the resistance of a wire are:
1. The length- the increase in length could increase the resistance.
2. The thickness of the core.
3. The material of which the wire is made up of- e.g. Copper,
constantan and nichrone.
4. The number of strands within a wire:
5. The amount of current flowing through the wire.
For this experiment, the factors which will be tested and measured
will be the length of the wire, the material of which the wire is made
from to see whether it affects the resistance, and seeing whether the
variable resistor also affects the wire in any way.
Apparatus
* Power pack
* 9 strands of copper wire, 0.193 mm thick, 30 cm long.
* 9 strands of nichrone wire, 0.193 mm thick, 30 cm long.
* 9 strands of constantan wire, 0.193 mm thick, 30 cm long.
* Ammeter, 10 amps max.
* Voltmeter, 20 volts max.
* Variable resister
* Heat proof matt.
* 7 wire leads.
* 2 crocodile clips.
* Ruler.
* Scissors.
Diagram:
Method
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Firstly collect all the apparatus needed to complete the investigation
and set the right apparatus into the correct positions.
Start of by measuring the volts and amps of one of the wires at a low
resistance, whilst always keeping the current the same for each time
at 6v. This wire should be 30 cm to start of with. When the volts and
amps have been measured, switch off the power pack between each
measurement so that the current is cut off. When this is done, cut off
5 cm of the wire and measure the volts and amps of the now 15 cm long
I also decided to use a wooden block to keep hold of the wire, because
All of the sources of current to the equipment should be isolated and signs need to be fixed to ensure that the nature of the equipment is known
I will start with 0.5 amps, working systematically, I will note
Finish off the circuit by connecting the output of the multimeter to the positive of the battery clip (if this is completely correctly, it should look like the image
it to a 5V power supply as a more convenient way of measure. As the
longer it will take electrons to get to the end of the wire. This is
equation V = IR. V - volts, I - current and R - resistance. I plotted
Ø I read from the ammeter each time I cut down the length by using
the nail. We then switched on the power supply and set the voltage to 4 V. We tested the number of paper clips the nail would pick up, each. time turning the power supply off and winding the coil five more times.
You can make an electric current in a wire if a wire is at right
This is know as resistivity. The factors I can investigate are : Ÿ Temperature Ÿ Length Ÿ Cross-sectional area/width Ÿ Material (resistivity) The factor I shall investigate is the length of a wire. Background Knowledge Resistance is when electrons travelling through the wire are impeded by the atoms within the wire. Since the electrons are charge carriers when they collide with the atoms in the wire less pass through.
The purpose of this experiment is to see if a potato can produce enough electricity to light a light bulb. Electricity is a kind of energy that can move from one place to another or stay in one place. The energy that can move from one place to another is called an electrical current. This experiment will try to create an electrical current by using a potato as part of a circuit. A circuit is a circling path that the electricity will follow. A circuit can be created when electrical materials are attached to wire, but if there is a break in
-Voltmeter -Variable resistor -Power Supply -Various diameters of wire -Crocodile clips -Metre ruler [ IMAGE] Diagram:.. Secondary Source - (Obtained in A-level PHYSICS by Roger Muncaster). Page 536 - "The 'Page The electrical resistivity of a material is defined by R = L / A Where R = Resistance of some conductor(Î).
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You take voltage measurements by counting the number of divisions a waveform spans on the oscilloscope's vertical scale. Adjusting the signal to cover most of the screen vertically, then taking the measurement along the centre vertical graticule line having the smaller divisions makes for the best voltage measurements. The more screen area you use, the more accurately you can read from the screen.