Page
  1. 1
    1
  2. 2
    2
  3. 3
    3
  4. 4
    4
  5. 5
    5
  6. 6
    6
  7. 7
    7
  8. 8
    8

The aim of this experiment is to investigate the relationship between the current, voltage and resistance through the use of a fixed resistor and a filament lamp.

Extracts from this essay...

Introduction

Aim The aim of this experiment is to investigate the relationship between the current, voltage and resistance through the use of a fixed resistor and a filament lamp. Hypothesis Based on knowledge of Ohm's law it can be hypothesised that when an increasing voltage and current is passed through a filament lamp the resistance would increase in an irregular fashion, so that a graph similar to the one given below would be seen (figure 1). This curved graph would be expected due to temperature increases in the filament lamp. It can also be hypothesised that when current is passed through a fixed resistor a straight line graph would be obtained (figure 2) this is explained in figure 3. Circuit Diagrams Equipment Fixed resistor & Filament Lamp- to impede and obstruct current flowing through circuit Ammeter- to measure current flowing through the circuit Voltmeter- to measure the voltage present in the circuit and to make sure the power supply is correctly calibrated. Power Supply- to act as the adjustable power source for the circuit Wires- to connect the circuit components. Tangles were removed from the wires as not doing so could result in erroneous values being obtained in the experiment, as using several different wires or tangled wires during the experiment could lead to varied resistance and poor fair test (Figure 6).

Middle

Carry out steps 3-5 again. 8. Once readings for filament lamp and fixed resistor are tabulated clear up equipment. 9. Plot an I-V graph for the fixed resistor and Filament Lamp. Variables The controlled variables in this experiment are the resistors and equipment used. The input variable in this experiment is the voltage. The output variables of this experiment are the current and resistance. Tables of results Table 1 Circuit with fixed resistor Voltage (V) Current (A) 0.00 2.10 4.10 6.20 7.90 10.00 12.10 0.00 0.20 0.44 0.58 0.71 0.92 1.10 Table 2 Circuit with filament lamp Voltage (V) Current (A) 0.00 1.00 2.00 4.00 6.20 8.30 10.20 12.10 0.00 0.46 0.74 1.10 1.36 1.54 1.66 1.74 Table 3 Circuit with fixed resistor Point of graph gradient measured Resistance (?) Throughout experiment (10.92) ~11 Table 4 Circuit with fixed resistor Point of graph gradient measured Resistance (?) A 2.86 B 6.67 C 32.70 Analysis of Results Both graphs produced results that should be expected by the types of resistor used. The graph for the fixed resistor is a straight line through the origin. The slope of the line was unchanged i.e. no tapering off. This is what should be observed when fixed resistors are used.

Conclusion

The experiment was also successful since there were few anomalies, only one for the fixed resistor. Thus it can be assumed that our results were accurate given the sensitivity of our equipment. We tried to resolve these anomalies by doing these tests again, however this resulted in getting the same figure. We can assume that the equipment is not to blame since it was kept the same throughout the experiment. The experiment was conducted in a safe environment and all precautions taken before the experiment paid off as no accidents took place. To conduct a fair test it would have been practical to use averages for a series of current readings. This could be done by using two different sets of equipment, conducting the experiment on each set and averaging the values. This could help us reduce the margin of error in any anomalies found. It may have been interesting to investigate the same aim with a wider range and more sensitive set of equipment. Smaller increases of voltage on the PSU would have allowed us to plot the graphs with more accuracy. If possible it would have been interesting to use a diode. We may also have adjusted variables such as the thickness, length and type of wire used to investigate the effect these factors have on Ohm's law and our graphs. we would also investigate how changing the circuit diagram would have affected our results.

The above preview is unformatted text

Found what you're looking for?

  • Start learning 29% faster today
  • Over 150,000 essays available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Over 180,000 student essays
  • Every subject and level covered
  • Thousands of essays marked by teachers

Related AS and A Level Electrical & Thermal Physics

  1. Single Phase Transformer (Experiment) Report.

    This will have an effect on the efficiency of the circuit aswell. Transformers can achieve maximum power transfer between the source and the load, by a method called resistance matching, using the formula below: - R1 = N1 2 RL N2 This formula allows the resistance of R1 to equal

  2. Investigate the current - voltage relationship for a resistor and filament lamp. To determine ...

    A gradient can be calculated to determine the resistance. A curved graph will show the alternative, that it is not an ohmic conductor. The p.d and current are not proportional. Ohms law can be presented mathematically by the equation V = IR which can be compared to the equation of

  1. Investigation into the resistance of a filament lamp.

    We know that Voltage is directly proportional to the current and Resistance is inverse proportional to current. I? V I ? 1 If we combine these two equations together we get I=V/R, if we re-arrange this formula we get ohm's law V=I.R.

  2. Investigating how temperature affects the resistance in a wire

    it away from the edge of the desk so it wouldn't fall off or tip and burn someone. Because of the fact that water and electricity was used in this experiment, I took careful care to always turn off the current after I had finished experimenting and to not spill any water.

  1. Investigation into the resistance of a filament lamp

    Prediction I predict that by increasing the resistance we will also increase the temperature of the filament lamp. Also the filament is not an ohmic conductor. This is because we know that at high temperature the ions have more kinetic energy then they would have if the temperature was low,

  2. Electronic Components.

    So a coil carrying a current in a magnetic field will twist, this is used in an electric motor. Can be used in tape players, toys and electric cars. Voltmeter Measure A voltmeter measures the electrical pressure difference across an electrical component.

  1. Investigating the factors affecting the size of current flowing through a length of resistivity ...

    3. The plates were always inserted in the correct place to about the nearest millimetre to ensure that the values for the length of the putty are accurate. 4.

  2. The aim of the experiment is to verify the maximum power theorem and investigate ...

    2 The scale of the spring balance was set properly to zero. 3 The sand paper was placed on the table. 4 A wooden block was placed on the table. 5 The wooden block was connected to the spring balance in series.

  • Over 180,000 essays
    written by students
  • Annotated by
    experienced teachers
  • Ideas and feedback to write
    your own great essays

Marked by a teacher

This essay has been marked by one of our great teachers. You can read the full teachers notes when you download the essay.

Peer reviewed

This essay has been reviewed by one of our specialist student essay reviewing squad. Read the full review on the essay page.

Peer reviewed

This essay has been reviewed by one of our specialist student essay reviewing squad. Read the full review under the essay preview on this page.