Monday, April 15, 2019
The resistance of a wire varies with its length Essay Example for Free
The granting immunity of a electrify varies with its continuance EssayTo investigate how the resistance of a cable varies with its length Equipment Needed o berth pack o 5 wires o Voltmeter o continuance of wire o Ruler o Ammeter o Crocodile clip Circuit Diagram Prediction The equivalence V=IxR is how you find the resistance rate. Im now going to re-arrange it to R= V for this to work the temperature has to stay I Constant or it will not work. So I predict that if I increased the length of the wire the resistance will be increased. So I think that if you double the length of the wire the resistance will be doubled. Method o Collect the equipment and set up the circuit by measuring the wire o Turn on the power pack.o Slowly increase the power o Connect the crocodile clip onto the copper wire to make the circuit complete. o Using a ammeter to measure the t whollyy of current in the circuit o Using a voltmeter to measure the amount of voltage across the circuit o Record res ults Repeat this with all the different lengths on the wire. excessively on the experiment make sure that you read the meter from directly in front by using parallax. Another thing makes sure that the needle is not moving around this then makes the criterion correct. Fair Test To make this a fair test Im going to keep everything the same in each test apart from the length of wire.The wire will be the same thickness and solid every time. Safety Its important that the wire does not get to hot that it burns. To prevent this from happening I wont let the current go any higher than 2amps. Preliminary work Current (A) mensuration (CM) Voltage (V) 2. 0A 10CM 0. 4 1. 5A 10CM 0. 3 1A 10CM 0. 2 0. 5A 10CM 0. 1 Current (A) Measurement(CM) Voltage(V) 2. 0A 90CM Off scale 1. 5A 90CM 3. 4 1. 0A 90CM 2. 5 0. 5A 90CM 1. 0 We mulish not to use a current of 2 Amps because it melts the wire. The other thing was we decided not use 90CM because one of the readings was off the scale. Practical Resul ts Length (CM).Current (A) Voltage (V) Corrected opponent ( ) CorrectedLength (CM) Current (A) Voltage (V) Corrected foe ( ) Corrected Length (CM) Current (A) Voltage (V) Corrected Resistance ( ) Corrected Our meter read 0. 1V even when no circuit was connected so I had to reach this reading off all the results which is why there is a corrected column.Length (CM) Average resistance (ohms) Conclusion I have noticed that as the length of the wire increases the resistance also increases. This happens because This all happens because the resistance has doubled like I said in my prediction. I checked this by aspect on my graph E. g. 20CM= 0. 44 40CM=0. 88 80CM=1. 76 See each time it has doubled. Evaluation We ensnare out that there was an error in our voltmeter which meant our first point was on 0. 1. This made our results incorrect which meant we had to re calculate the numbers.We read all our results to one decimal point instead of two. I have an ridiculous point at 20cm. I can s ee from my results there was a error at 15amps. If I ignore this result and take an average of 0. 5+1. 0amps I get a point that lies on my line. I have shown this on my graph in red. This error accrued by reading the cadency wrong. Holly Atkins Page Show preview only The above preview is unformatted text This student written pick of work is one of many that can be found in our GCSE Electricity and Magnetism section.