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

Investigating Ohms law

Extracts from this document...

Introduction

Physics Coursework

Investigating Ohms law

Introduction

Georg Ohm was born in Erlangden and educated at the university there. He became a professor of mathematics in 1817 in the polytechnic school of Nuremberg in 1833, and in 1852 became a professor of experimental physics in the university of Munich, where he later died.

        In 1826, Georg Ohm discovered the current flowing through a metal wire was proportional to the potential difference across it (providing the temperature remained constant). Proportional means that if you double the potential difference the current will also double.

Ohms law:

Where:

‘V’ is the voltage in volts (V),

‘I’ is the current in amps (A),

‘R’ is the resistance in Ohms (Ω).

Aim

In my coursework I will be looking at the following three components:

  • A light bulb
  • A thermistor
  • A metal wire

My aim is to carry out experiments on these three components and find which component out of the three obeys Ohms law.

Hypothesis

        Ohms law gives the relationship between voltage, current and resistance in electrical circuits. Voltage is the push of the charges. Current is the flow of electricity. Resistance is the obstructions in the path of the current; therefore it slows the current down. There are four factors affecting resistance. They are:

  • Length
  • Cross-sectional area
  • Material
  • Temperature.

...read more.

Middle

5

0.59

5

0.60

5

0.60

6

0.73

6

0.71

6

0.71

6

0.72

8

1.00

8

1.00

8

1.00

8

1.00

10

1.25

10

1.29

10

1.29

10

1.28

12

1.52

12

1.52

12

1.54

12

1.53

Thermistor

Repeat 1

Repeat 2

Voltage (V)

Current (mili amps)

Voltage (V)

Current (mili amps)

Voltage (V)

Current (mili amps)

Average voltage (V)

Average current (mili amps)

0

0

0

0

0

0

0

0

2

6.00

2

5.10

2

6.60

2

5.90

3

8.60

3

7.30

3

8.90

3

8.27

4

11.30

4

9.70

4

11.70

4

10.90

5

14.20

5

12.10

5

14.50

5

13.60

6

17.20

6

14.90

6

17.70

6

16.63

8

23.80

8

20.80

8

24.20

8

22.93

10

39.00

10

34.10

10

39.60

10

37.57

12

67.50

12

65.80

12

69.80

12

67.70

Light bulb

Repeat 1

Repeat 2

Voltage (V)

Current (A)

Voltage (V)

Current (A)

...read more.

Conclusion

Evaluation

        By doing this investigation, I have found many things. Firstly I found what voltage, current and resistance are and what effect voltage and current have on the resistance of different components. I have also found how resistance can be calculated and how three factors (voltage, current and resistance) can form a formula in relation to each other making either one the subject of the formula. I also learnt how to set up an ideal practical experiment, obtain my results, tabulate them, convert them to graphs, analyse them and interpret my graphs. I also learnt to implement safe working procedures using a variable resistor. This ensured that the component was not left on in the circuit for a long period of time.

        There are also some improvements I could have made to my experiment in order for it to be even more accurate. One way I could have improved my experiment is by using a sensitive millimetre to obtain a very accurate set of results. I could have done is increasing my voltage in 1 volts in order to get more readings.

...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. Investigate how the temperature affects the resistance of a thermistor.

    was in one of the results record I could have taken down the resistance at a higher temperature than it should have been which would therefore affect the average. In which case, the anomaly is due to carelessness and inaccuracy.

  2. Free essay

    Resistance of a wire

    To get the most accurate readings from our ammeter and voltmeter we used digital models to get results to the 2nd decimal point. Temperature surroundings have to be taken into consideration as they are almost impossible to maintain perfectly. Sunlight frequently shone through the windows and this could have easily caused slight but important differences in the wire resistivity.

  1. Using an LDR to detect the intensity of plane polarised light allowed through a ...

    Systematic Drift What is 'systematic drift'? Systematic drift is defined as the change in results that can be achieved, due to something changing over time. In this case, for example, were I doing my experiment in the open air, then naturally change in temperature and ambient light would affect my coursework.

  2. To prove ohms' law, and to study the relationship between current and potential difference ...

    As I decreased the resistance the current increased, thus increasing the voltage. But as I decreased the resistance the current increased at a small rate, by just increasing 0.01A, and that is because the resistance is great. In the fourth experiment where I tested with two resistors of 10?, and 12?

  1. Investigating the effect of 'length' on the resistance of a wire

    possibility of them having collisions with the metal ions is higher and so the greater the resistance. Based on the scientific knowledge I have just mentioned I predict that as the length of the material or wire increases its resistance will also increase, so if the length is doubled then the resistance will also be doubled.

  2. physics sensor coursework

    Thus, the more delocalised electrons there are, the more charge that can be carried, and the lower the resistance. An LDR is made out of a semi conducting material, which means that it has electrical properties intermediate to that of conductors and insulators.

  1. Physics coursework

    Beaker of distilled water To provide an environment where the temperature change can take place so the thermistor's resistance can change.

  2. Characteristics of Ohmic and Non Ohmic Conductors.

    This is the structure after the potential difference is applied. The resistance in metallic conductors increases as temperature increases. The resistance increases because the atoms of the metal start to vibrate and so making it difficult for electrons to pass through.

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