• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

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 document...


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 increasing voltage and current is passed through a filament lamp the resistance would increase in a non-linear fashion, such that a graph similar to the one given below would be obtained (figure 1). This non-linear 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 the relationship between V and I would be expected to be linear such that a straight line through the origin would be obtained (figure 2). In addition the readings on the ammeter and voltmeter would both change accordingly as expected. The shape of a fixed resistor current-voltage graph (I-V graph) is explained in figure 3 since the three variables are related through Ohm's law. 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 experiment, as using several different wires or tangled wires during the experiment could lead to varied resistance and poor fair test (Figure 6). ...read more.


The PSU was set to zero volts and the circuit was turned back on after making sure that the filament lamp was in tact. The voltage readings were then repeated as before and were inserted in another table and averaged out. Following this the equipment was cleared away after making sure that hands were dry. The tables were then plotted onto graphs. Method in summary: 1. Apply safety precautions. 2. Gather equipment and connect it according to figure 4. 3. Recheck for safety and turn the circuit on. 4. Increase the Voltage by 2V every reading and note the current reading on the ammeter. 5. Once 12V is reached switch the PSU off. 6. Replace resistor with a Filament Lamp 7. 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 variable in this experiment is the 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 (?) ...read more.


The experiment was also successful since there were few anomalies, only one for the fixed resistor. Thus it can be assumed that the results obtained 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 may assume that the equipment isn't 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 in that no accidents happened. It would have been practical in the interest of conducting a fair test to use averages for series of current readings. This could be done using two different sets of equipment, conducting the experiment on each set and averaging the values. This could help us reduce error margin 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 graduations 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. However given the amount of time we had, it would not have been possible to further complicate the experimental design. We may also have adjusted variables such as the gauge, length and type of wire used to investigate the effect these factors have on ohms law. It may also have been of interest to us if we investigated how adjusting the circuit diagram would have affected our results. However this may have been a little advanced for our level at present. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our University Degree Physics section.

Found what you're looking for?

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

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related University Degree Physics essays

  1. The aim of this experiment was to set up, calibrate and use a model ...

    The optical system depends on the skill of the operator in correctly adjusting the position of the eyepiece using manual controls and judging the position of best focus. A focimeter can also be used to check the cylindrical lens power and axis, as well as the prismatic correction (both power and direction)

  2. Is Human Activity Responsible For Increased Global Warming?

    (http://www.ace.mmu.ac.uk/eae/Global_warming/older/Carbon_Dioxide.html) However, the argument against this is that yes, natural sources do produce carbon dioxide as well but they also remove it at a nearly identical rate and the balance has maintained at a stable level for thousands of year prior to the industrial revolution, so there is still nothing to explain the increase in carbon dioxide concentrations.

  1. Torque Physics Lab Report. The purpose of this experiment was to help understand ...

    If the clamp were to have been inverted, where the bar is supported at a point above the center of gravity, you wouldn't een be able to balance the meter bar because it is not in the center of gravity it would just be slack and hang down.

  2. The aim of this report is to give a summary of the experiments executed ...

    scale, divided by the percent change in the value of the resistor (Table 1). 5 - Using the counter, display a dynamic ramp, clock signal of counter around 500Hz (Figure 3).

  1. Investigating factors which affect the period time of a simple pendulum

    * The clamp stand should be secured because rocking will distort the results. The clamp stand is secured in place by a G-clamp. * The angle should be measured accurately using the protractor. Amplitude Results Angle (degrees) Period of 10 Oscillation (s)

  2. Electrical and electronic principles - Application of circuit theory.

    An oscilloscope was used to determine voltage and phase angle at the break-point. The results obtained from the oscilloscope were. Obviously these values fall short of the calculated values, however this is most likely due to the tolerances of the discrete components.

  1. Investigation into the relationship between the length of a wire and the resistance

    Do this for the 32, 36 and 40 Standard Wire Gauge (the lower the number the thicker the wire). * All wires will be of the same materiel, in this case of Constantine, in order to make the experiment a fair test.

  2. Double Slit Interference

    Then the paper was removed and the distances between the central maximum and the other maximums were measured with meter stick. Also the distance between the screen and the slit disk was measured and recorded. After that, the slit disk was rotated to a new double slit with 0.04 mm

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work