• 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...

Introduction

Abdul Mufti                                               Centre Number: 13329                                 Candidate Number: 4138  

10. F

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.

image00.pngimage01.png

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.

image09.pngimage10.pngimage11.pngimage02.pngimage03.png


Circuit Diagrams

image04.png

image05.png

image06.png

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

Wiresto connect the circuit components.

...read more.

Middle

In order to apply Ohm’s law we need to know two of the 3 variables. In this experiment we will know the voltage and current. Therefore by rearranging Ohm’s law we can calculate the resistance.

  • A steady increase in resistance, in a circuit with constant voltage, produces a progressively (not a straight-line if graphed) weaker current. 
  • A steady increase in voltage, in a circuit with constant resistance, produces a constant linear rise in current.

In this case, Ohm’s law is needed to calculate the resistance of the fixed resistor and the change in resistance as the filament lamp gets hot. For each case gradient from the appropriate graphs will be used. Resistance can be varied by using a variable resistor, by altering the gauge or by length of the wire or by changing the temperature. If a longer wire is being used then the resistance increases as the electrons have to travel further than in a short wire. If a thicker wire is being used then the electrons have more space to move and therefore resistance is decreased. If a thinner wire is used then the resistance will increase as the electrons cannot get around the circuit easily.

Method

The work surface was insured to be dry and clean. Bags, stools and other possible obstacles were removed from the work area. The equipment was collected according to the list given and verified by close inspection to be clean, non-corroded and undamaged.

...read more.

Conclusion

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.

Bibliography

GCSE double Science Physics – CGP – ISBN: 1-84146-401-5

New Modular Science for GCSE, (Vol 1), - Heinemann (1996) – ISBN: 0-43557-196-6

AQA GCSE Science syllabus (2001).

...read more.

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

    Therefore you wouldn't even find the accurate position where it is level. This would have skewed the results, making inaccurate readings and calculations. In part IV, if the meter bar were to be held at an incline of 30 degrees angle above the horizontal by the spring balance, the spring

  2. SELECTED PROBLEMS OF MODERN PHYSICS I. THE PHOTOELECTRIC EFFECT

    How is the hydrogen spectrum explained in Bohr model? In order to explain emission of hydrogen spectrum Bohr introduced a third postulate into his theory. An atom emits light ONLY when it undergoes a transition from one stationary state t another of lower energy.

  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. Resistance. To solve this question, we need to consider the resistivities, lengths and cross-sectional ...

    and A is the cross-sectional area of the material perpendicular to the force (in in2, cm2, or m2). Modulus of Elasticity: Modulus of Elasticity (typically represented by the symbols Y or E, and measured in pounds of force/in2, dynes/cm2, or pascals)

  1. Double Slit Interference

    Slit width a (mm) Slit separation d (mm) Slit-to-screen distance D (cm) Calculated slit separation (mm) Percentage difference (%) First order (m=1) 3.0 0.5 0.04 0.25 105.30 0.05 0.23 0.05 8% Second Order (m=2) 6.0 0.5 0.04 0.25 105.30 0.05 0.23 0.05 8% Table 4 (0.04 mm / 0.25 mm Double Slit)

  2. Free essay

    Semiconductor bandgap Report. In this work, transmission spectroscopy was used under continuous light ...

    49 0.019182 0.06266 520 769 17 26 0.022107 0.03381 500 740 18 26 0.024324 0.035135 480 690 17 26 0.024638 0.037681 460 630 18 25 0.028571 0.039683 440 547 19 25 0.034735 0.045704 420 429 17 26 0.039627 0.060606 400 96 18 25 0.1875 0.260417 380 51 18 25 0.352941

  1. 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.

  2. The Current Balance

    This mechanism was used to return the knife edges back to their initial position in case they moved a little during the experiment. Using this mechanism to raise the knife edges clear of their supports and then lowering them back down caused the frame to oscillate freely.

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