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

Does a light bulb obey Ohms law.

Extracts from this document...

Introduction

Does

A

Light

Bulb

Obey

Ohms

Law

Aim:

My aim is to carry out an investigation to find out whether a filament light bulb obeys ohms law. I am carrying out an experiment to find the different resistances and currents created by a light bulb at different voltages. Because of the light bulb, it glows white-hot when fully on, the resistance will change at different voltages. When the voltage is low and the bulb is not very bright, it won't be as hot and therefore it will have less resistance. But when the current is high and the bulb is brighter, it will have a high resistance.

Theory:

Ohms law suggests that if you were to increase the P.D (potential difference) across a resistor then the current flowing through a resistor will increase. This means that the current would evenly go up as the P.D increases.

Definition:

Ammeter:

This is a device that measures the current of electrons in Amps. It has to be placed in series on the circuit.

Voltmeter:

...read more.

Middle

  • 1 Ammeter
  • 1 Voltmeter
  • 1 Power Pack
  • Wires
  • 1 Bulb

I will put together the circuit by using the equipment I mentioned before. I will join the ammeter and voltmeter to the power pack using wires and join the light bulb to the ammeter and voltmeter using wires. I will record the results every 0.5 volts. I will record the results shown on the ammeter.

This is the circuit I will be using to perform my experiment:

Fair Testing:

To ensure my experiment is a fair test I will use all of the same equipment for the whole experiment. This is because each piece of equipment has their own faults in them. If I use a consistent set of equipment then I will have a more consistent group of results. I will measure each voltage three times so I can get a wider variety of results. Because we are working in a classroom there are some problems which may affect our results inaccurate equipment, old equipment, room temperature and lack of space to work with.

Results:

Analysis:

...read more.

Conclusion

To improve the experiment, I would probably have to be really professional and a lot more scientifically precise in how I carry out the experiment. I would need to make sure there is a consistent classroom temperature, as changing temperatures may affect the filament's own temperature. If I had more time, I could try the investigation with different equipment to what I had already used. This could prove that the equipment I used doesn't matter in the experiment, and it's the fact that how I carry it out which is key.

To extend the project further, we could carry on the voltages to twenty, or twenty-five to see what happens to the results and graphs then. We even could carry the experiment on until the filament melts, and see how much voltage it can take. Also, we could add a lamp or two into the circuit and see if this affects the resistance in any way. Maybe instead of a power pack, replacing it with a couple of cells and also adding a variable resistor into the circuit.

...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 Ohms law

    Voltmeter: To change the voltage in order to change the current. Three components, which are: i. Light bulb ii. Thermistor iii. Metal wire I will use a variable resistor instead of the metal wire to give a constant length of the metal wire.

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

    Safety Whenever using mains electricity in experiments you must be careful to avoid electric shocks. Make sure that when the experiment is finished tthat you turn off all electricity. Do not let wires connected to electricity make contact with your skin.

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

    The large current results in a small resistance where it's 5.5?, and a large voltage, because the power supply has to push a large amount of current. Conclusion: From the experiment I can conclude: 1. In a series circuit, the same current flows through each part of the circuit 2.

  2. The aim of our investigation is to investigate Ohms Law.

    Step 3- Switch the power pack on and record the voltage and current Step 4- Turn the power pack off and move the crocodile clip to 90cm Step 5- Turn the power pack back on and record the Voltage and Current for 90cm Step 6- Repeat this for 80cm, 70cm, 60cm, 50cm and 40cm.

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

    * I will be careful when touching the wire, as it may be hot. * Start on the lowest current, so the wire then will not melt or burn instantly. * Put the variable resistor in the largest resistance so as to make sure that not too much current flows through the circuit.

  2. Investigating The Characteristics Of A Light Bulb.

    The bulb became extremely bright as we turned the rheostat up. 12 volts: V/V I/A 1.42 0.72 2.02 0.83 3.20 1.02 4.67 1.23 7.85 1.59 11.18 1.90 As a result of this preliminary work, I decided to use the power supply on 9 volts.

  1. Sensors Project Report

    Since the temperature at any time will be slightly different from one another, so the reading may not be accurate enough. 4. After long time of experiment the potentiometer starts to heat up. When the temperature increase, the resistance of the potentiometer will increase and the potential difference (voltage)

  2. Sensors cwk. The aim of this coursework is to construct a potential divider circuit ...

    This is a model of what my circuit will be like: After connecting my circuit as above, I will go to a dark room and by using a 10V light bulb, I will try to obtain results as follows: > Firstly, make sure that the LDR is in direct sight of the light bulb.

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