I was given three different types of metals and asked to find the resistivity of all three. This was because I wanted to find the best conductor and make a suitable recommendation as to how this metal could be used in the industry. The resistance of a metal is affected by the length and the diameter of the wire. A long wire has more resistance than a short one, while a thick wire has a lower resistance than a thin one. Resistivity is part of the determining factors of resistance. Equation to find resistivity R = pl A Where p = resistivity L = length A = area R = resistance Plan.
In order to find the resistivity I will conduct the following laboratory experiment to find the resistance of the wires. Apparatus Meter rule Micrometer Multimeter 3 wires (Copper, Nichrome, Constantan) 2 connecting wires + 2 crocodile clips Planned method I shall firstly measure the length of the given wire to the nearest mm using a ruler. I will then measure the diameter of the wires using a micrometer my calculations will be recorded in mm. After revising my plan I have decided to repeat my diameter measurements and resistances record three times for each wire so that I can find an average and use this recording later.
This will hopefully eliminate the error magnitude. I will then measure the resistance of each of the wires in ohms using a multimeter this will be done by connecting crocodile clips to the ends of the wire. I shall keep records of my data in a table as I carry out the experiment. After finding the diameter and resistance of the wires this will enable me to find the resistivity of the wires. The possible errors that could be involved in the experiment are the diameter of the wires. As the measurements were rounded of to the nearest mm the magnitude of error can also be calculated
In copper 0. 275mm was the first reading I collected Meaning the max reading would be = 0. 2755 And the minimum being = 0. 2745 Therefore 0. 275mm (+or-) 0. 0005 Absolute error = 0. 0005 % error = 0. 0005 x 100 0. 275 =0. 182% (3. s. f) (My results and tables can be found on a separate piece of paper)
The comparison of my results and the text book results Copper The value I calculated using my data was 7 The most common value found in text books % magnitude error This percentage in error is not that large compared to the large difference in conditions when the experiment was being carried out. When conducted in a proper laboratory being accurate is more essential and so the apparatus used is of higher accuracy than the one that we were able to use. When we were recording the length of the wire we used a ruler this may not have been as accurate as expected. Copper is not the best conductor, however. Silver is better and Gold is better.
These are expensive metals and are used in special applications only. There is also a group of materials that are specially created that are not conductors until certain impurities are added. Then they become very good conductors, better than any naturally occuring materials. Also, cooling materials down to near absolute zero (Kelvin) make some of them nearly perfect conductors. At such a low temperature the atoms no longer vibrate and electrons are free to move. I don’t understand your experiment though. What did the wax melting prove?
A better conductor generates less heat when carrying electrical current. Gus Conclusion Copper is the best conductor of the three metals. This is mainly because the electrons in copper can be more easily transferred from one to another. This is important because electric current is based on the flow of electrons through the conductor. Show preview only The above preview is unformatted text This student written piece of work is one of many that can be found in our GCSE Electricity and Magnetism section.