• 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

Find out how the current through a filament lamp varies with the potential difference across it.

Extracts from this document...

Introduction

Investigation into the resistance of a filament lamp

Physics A 3883

Planning

Aim

 For this investigation I have been asked to find out how the current through a filament lamp varies with the potential difference across it and hence determine how the resistance of the filament and the power supplied to it vary with the potential difference across it. I will also make estimates of the temperature of the filament for different potential differences.

Key factors

Independent variables:

  • Current (Current will be measured with a digital ammeter/multi meter)
  • Temperature (Thermometer to measure surrounding temperature)

Dependent variable

  • Resistance
  • Voltage (Will be measured with a digital voltmeter)

Controlled variable  

  • Filament lamp

The range of readings that I am going to take will be from 0 volts to 10 volts this is because it will give me a good set of data to work with.

 I will increase the voltage by one volt each time.

To make sure I get good accurate fair results I will repeat the process at least 3 times.

When I do repeat the process I will make sure that I leave all the equipment as it is and not replace bits or add or remove components.

...read more.

Middle

0.13

0.12

0.14

0.13

0.69

0.75

0.64

0.69

0.10

0.15

0.13

0.16

0.15

0.67

0.77

0.63

0.69

0.15

0.22

0.21

0.21

0.21

0.68

0.71

0.71

0.70

0.20

0.27

0.28

0.29

0.28

0.74

0.71

0.69

0.71

0.25

0.31

0.34

0.33

0.33

0.89

0.86

0.76

0.84

0.30

0.36

0.37

0.37

0.37

0.83

0.81

0.81

0.82

0.35

0.40

0.41

0.40

0.40

0.95

0.95

0.88

0.93

0.40

0.44

0.45

0.45

0.45

0.98

1.00

0.89

0.96

0.45

0.48

0.48

0.49

0.48

1.00

1.00

0.92

0.97

0.50

0.52

0.53

0.52

0.52

1.04

1.02

0.96

1.01

1.00

0.75

0.75

0.76

0.75

1.33

1.33

1.32

1.33

2.00

1.05

1.06

1.05

1.05

1.90

1.89

1.90

1.90

3.00

1.26

1.27

1.27

1.27

2.38

2.36

2.36

2.37

4.00

1.46

1.47

1.47

1.47

2.74

2.72

2.72

2.73

5.00

1.64

1.64

1.64

1.64

3.05

3.05

3.05

3.05

6.00

1.79

1.80

1.80

1.80

3.35

3.33

3.33

3.34

7.00

1.94

1.95

1.95

1.95

3.61

3.59

3.59

3.60

8.00

2.09

2.09

2.09

2.09

3.83

3.83

3.83

3.83

9.00

2.21

2.22

2.23

2.22

4.07

4.05

4.04

4.05

10.0

2.35

2.35

2.35

2.35

4.26

4.26

4.26

4.26

Results

Results table1

Resistance for filament lamp at 0°C=0.68Ω

Calculated From: Average resistance of (0.01v to 0.10v)/10

I didn’t use the data from 0.10 volts to 0.50 volts in any working because the heat was rising so was no good for calculating the resistance of

...read more.

Conclusion

Also I would use the measured potential difference on the voltmeter as a variable rather that using it as a fixed variable because I could get even more accurate results.

Data

The main experiment went very smoothly, I got all the data that I wanted to but during the experiment where I was collecting the current for 0.01volts to 0.10 volts it was very had to collect accurate data because on the graph you can clearly see that there is a anomalous result (circled) this may have been human error or it could have been a random error like a power surge in the electric mains or a fault with the equipment. To overcome this in the future I would have a tolerance level for the current, e.g. if it wasn’t 0.20±2A then I would do it again, if it kept on happening then I would try changing some of the equipment, but then I would have to start all over again because of the differences in the equipment (if any). This would also give me a good indication if the original equipment was faulty, but the new equipment may and/or be faulty so I would have to make up my mind which to use.

©Will Trawin

2003

...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. In this experiment we had to investigate how the power dissipation of a filament ...

    Conclusion The aim of the experiment was to; find in this experiment if there was a relationship between power and p.d over a filament lamp.

  2. Electrical Properties of a Filament Lamp - Does a Filament Lamp Obey Ohm's Law?

    And as Ohm's law says, 'this is only true when the temperature is kept constant'. The scientific reason that heat affects the resistance is in the electons. The lamp's atoms vibrate violently when heated. The electrons meet the atoms, they hit them and lose some of their energy because the atoms knock them with a lot of force.

  1. The factors affecting the current flow through a conductor at a constant temperature.

    All the equipment was kept the same and the temperature also remained constant. I can see clearly from the Results Table and graph that resistance is proportional to current and voltage. As the resistance increased so did the current and voltage.

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

    When an electron leaves an atom the atom is then more positively charged and is unbalanced. Thus it will always want to get an electron back to the valence orbit to become balanced. As electrons are negative they will always be attracted to a positive atom.

  1. Investigation into the resistance of a filament lamp.

    So to find resistance we can re-arrange V=I.R to get; R=V/I What determines the resistance? > The length of the material (Example- 70 cm of copper wire will have high resistance then 60cm of copper wire) > The temperature (Example- the greater the temperature the greater the resistance, this is

  2. The aim of my investigation is to determine the specific heat capacity of aluminium.

    However the range 1210-1230 does not include the actual value for the specific heat capacity of aluminium which is approximately 900Jkg-1 oC-1. There must therefore be other reasons as to why these results are not accurate, I think this may be due to a lack of readings.

  1. Observe and record the brightness, voltage difference (the potential difference between two points in ...

    The current with this circuit that had three light bulbs had been .027 amps. Nevertheless, the lamps had become even less bright and quite dim. Circuit 4: My hypothesis for this circuit had been partly correct.

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

    Writing equipment was in place before the experiment was started. The equipment was then turned on. As the voltage on the PSU was increased it was confirmed on the voltmeter and the reading on the ammeter was noted. For the first circuit a total of 7 ammeter readings were taken and repeated.

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