• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month
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
  9. 9
    9
  10. 10
    10
  11. 11
    11
  12. 12
    12

Investigate the relationship between the variables V, R, and I in an electric circuit.

Extracts from this document...

Introduction

Experiment 3: Ohm’s Law                                                                    Date: 22.03.2004

Objective: 1) To investigate the relationship between the variables V, R, and I in an

                      electric circuit.

                  2) To analyze series and parallel connection in terms of V, R, I

                  3) To determine the relationship between current and voltage in a circuit that  

                      contain a filament bulb

Theory:

It is known that electrons flow through a conductor metal wires with an ease without any resistance. This means that nothing would prevent the flow of the electrons. In a normal case however, under normal conditions, a resistance in the wire would affect the flow of the electrons in much the same way that friction slows down a sliding box on a platform. To allow more electrons to move against the resistance of a wire, it is necessary to apply a potential difference between the two ends. One can calculate the potential difference needed to create a current, I if the constant resistance, R of the wire is known. The relationship between these three variables (R, I, V) is given through Ohm’s Law which stated that the potential difference, V in a wire is proportional to the current, I if the temperature and all other physical quantities are fixed. From the law itself, we have an expression:

V=IR

...read more.

Middle

image07.png

  1. The resistor is remove the next one used is chosen. The voltage is recorded in Table 1 as in step 5. The process is continued until all the resistors’ voltage recorded.

Part 2: Resistance in circuits  

  1. Three resistor of the same value is chosen. The set of colours is recorded in Table 2.
  2. The coded value of the resistors is determined and the value is recorded in the column labelled “Coded Resistance” in table 2. The tolerance value is entered as indicated by the colour of the fourth band under “tolerance”
  3. The multimetre is used to measure the resistance of the three resistors. The value is then recorded in Table 2.
  4. The percentage experimental error for each resistance value is calculated and is recorded
  5. The three resistors are connected to the series circuit by using the spring clips on the Circuit Experimental Board to hold the leads of resistors together without bending them. The resistance of the combination is measured as indicated on the diagram by connecting the leads of the Multimetre between the points at the end of the arrows.

image09.png

  1. A parallel circuit is constructed by using the combination of the two resistors and finally by using all the three resistors. The values for the circuits are measured and recorded.

Part 3: Voltage in circuits

...read more.

Conclusion

In part 2, the coded tolerance for the resistor is +5%. From the reading we obtain the percentage of errors is 1% and 2%. Thus it said that the data obtain is acceptable. In part 2, we conducted two experiment whereby in one experiment the resistor is arrange in series and in the other experiment the resistor is arrange in parallel. Base on the theory for series resistor we have:

image15.png

Thus the equivalent resistance in the circuit is:

image16.png

The rule for the total resistance when the resistor is arranged in parallel is as followed:

image05.png

As a conclusion we can say that the data obtain in the experiment obey the rule.

        In part 3, we found out that the voltage gets distributed in a series circuit with equal resistance when the value of the resistor is the same. The larger the value of the resistor, the larger the value of the resulting voltage.

        In part 4, a voltage versus current was obtained. At a certain point in the graph, a straight line is obtain which directly prove Ohm’s Law which stated that the voltage, V is proportional to the current, I and the slope of the graph is the resistance.

Conclusion

        As a conclusion, we found out that the voltage, V is proportional to the current, I. The relationship for the variable V, I, R is V = IR

...read more.

This student written piece of work is one of many that can be found in our AS and A Level Electrical & Thermal 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 AS and A Level Electrical & Thermal Physics essays

  1. Investigating the E.m.f and Internal Resistance of 2 cells on different circuit Structures.

    amps but I realised this was too inaccurate as the results were all rounded to the same value of 1 amps so therefore I decided to use milliamps which meant the current was measured to the nearest thousandth amp. This created more accurate results as the change in current was far more noticeable and therefore utilizable for the investigation.

  2. To Investigate How the Resistance of the Light Dependent Resistor Depends On the Current ...

    I have also chosen to take two repeats at each length and then take an average, to get reliable results EVIDENCE I1 (MA) First time Second time The average R (LDR) (?) I2 (MA) V2 (V) R (LDR) (?) I2 (MA)

  1. Investigation into the resistance of a filament lamp.

    (amps) (amps) Average Current(amps) Colour of the filament 0.50 0.45 0.43 0.42 0.49 Not glowing, grey 1.00 0.62 0.60 0.59 0.60 Not glowing, grey 1.50 0.67 0.68 0.65 0.67 Not glowing, grey 2.00 0.71 0.69 0.69 0.70 Not glowing, grey 2.50 0.78 0.75 0.74 0.76 Not glowing, grey 3.00

  2. Objective: l To rectify ...

    Sketch two waveforms to show the effect of putting on and off the C-cores of the inductor, and explain why it is better to use the C-cores in the inductor. Experiment Results and Data Evaluation: Time base= 2 ms cm-1 = 2�10-3 s cm-1 Power supply = 6 V

  1. I am going to investigate what the resistivity is of a pencil lead. ...

    0.44 0.443 1.00 0.55 0.54 0.55 0.546 1.20 0.66 0.66 0.67 0.663 1.40 0.84 0.85 0.85 0.846 1.60 1.11 1.10 1.10 1.103 1.80 1.28 1.26 1.30 1.280 2.00 1.46 1.45 1.45 1.453 As you can see from the graph, the line of best fit does not pass through (0,0)

  2. The aim of this experiment is to investigate the relationship between the current, voltage ...

    This also confirms my hypotheses as being correct. > When current is passed through a filament lamp the resistance would increase in an irregular fashion. > So that a curved graph would be produced due to temperature increases. Results for both resistors were as expected based on scientific knowledge of

  1. The potato - a source of EMF

    Ammeter: 0.02mA Voltmeter: 0.02V I could have added to the error bars by taking into account the human error however, because I did not carry out the experiment myself I cannot judge how precisely the reading were taken. There are two points where the error bars only just touch the trend line; this suggests that they could be anomalies.

  2. Diode Application in Rectifier Circuits

    As Vin becomes positive, the capacitor serves as a voltage double; since it has stored the equivalent of Vin during the negative cycle, it provides nearly that voltage during the positive cycle; this essentially doubles the voltage seen by the load.

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