Thursday, November 14, 2019
Resistance coursework - some useful things :: essays research papers
Resistance Coursework Planning: Aim Investigate how the length of a wire affects the current and resistance of a wire. Variables The variables that could change resistance are: †¢Ã‚     Length of the wire †¢Ã‚     Cross section area (thickness) †¢Ã‚     Changing materials †¢Ã‚     Changing temperatures The variable I am going to change in my experiment is the length of the wire. Prediction and Hypothesis I think as you increase the length of the Constantan wire, you also increase the amount of resistance. The current is the flow of electrons; the current is dependent on the amount of voltage, which is applied. Voltage is the push given to the current. The current has to go through a circuit, which contains resistance so if you increase that push you also increase the flow of the current. All materials have a slight resistance to electricity factors affecting the resistance are: Length, Voltage & Temperature and Surface Area. Preliminary Work Changing only the length of the wire Length     Voltage (V)     Current (A)     Resistance () Short     5.45     0.26     20.96 Long     5.56     0.24     23.16 Longest     5.58     0.19     29.36 Conclusion: the longer the wire, the higher the resistance Changing only the cross section area of the wire Thickness     Voltage (V)     Current (A)     Resistance () Single     4.73     1.45     3.26 Double     4.44     1.98     2.24 Triple     4.34     2.07     2.09 Conclusion: the thicker the wire, the lower the resistance Changing Materials Material     Voltage (V)     Current (A)     Resistance () Constantan     5.51     0.48     11.47 Aluminium     1.82     8.63     0.21 Conclusion: different materials conduct electricity better Changing Temperatures Temperature     Voltage (V)     Current (A)     Resistance () Cold     2.27     6.72     0.34 Hot     2.62     7.00     0.37 Conclusion I came to a conclusion that the decrease in current is the increase in resistance this is because the current although less of it they collide with the resistance causing a decrease in the output voltage. List of equipment and circuit diagram †¢Ã‚     Power pack †¢Ã‚     6 connecting leads †¢Ã‚     Push switch †¢Ã‚     2 crocodile clips †¢Ã‚     Wire (constantan) †¢Ã‚     Voltmeter †¢Ã‚     Ammeter †¢Ã‚     Meter sticks Circuit diagram: Analysing: As the length increased so did the resistance. This is because in a longer piece of wire the electrons have to push past more ions. The electrons have a negative charge and the ions have a positive charge. So energy is needed to keep the electrons flowing.
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