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

Ohm's Law Physics Lab #20

Extracts from this document...

Introduction

Ohm’s Law

Physics Lab #20

Name: Diana Abou Hassan

Partners: Sara Jaber

Michael Muhanna

Rami Jachi

Date Performed: 14/11/2002

Date Due: 21/11/2002

Teacher: Mrs. Khoury Saab

Objective:

The objective of this lab is to determine the relationship between the potential difference across a conductor and the electric current through it. \

Materials:

  • Low voltage variable DC power supply\
  • Two different resistors
  • 2 digital multimeters
  • connecting wires

Procedure: Please refer to lab sheet.

Data Collected:

Resistor 2

Voltage (V)

1

1.5

2

2.5

3

3.5

Current (mA + 0.01mA)

0.42

0.72

1.16

1.56

1.91

2.30

Potential Difference (V + 0.001V)

0.526

0.877

1.404

1.893

2.324

2.796

...read more.

Middle

2.359

2.793

Resistor 2 = 1.202 KΩ

Resistor 7 = 5.07 KΩ

Light Bulb

Before lighting up:

Voltage (V+ 0.0001V)

0.0069

0.0781

0.5780

0.6560

0.7590

Current (mA+ 0.01mA)

0.90

10.50

81.30

92.40

109.70

The light bulb lit up at:

Voltage (V+ 0.0001V)

1.0010

Current (mA+ 0.01mA)

149.30

After lighting up:

Voltage (V+ 0.0001V)

1.6090

1.8310

2.116

Current (mA + 0.01mA)

182.30

200.00

223.50

Data Analysis:

Calculate the slope of each graph:

Sample Calculation:

Slope of Resistor 2 = (y2 – y1) / (x2 – x1)

                                = (2.30 V – 0.42V )/(2.796mA – 0.526mA)

                                = (2.30 V – 0.42V )/(0.

...read more.

Conclusion

Sources of Error:

        The manual adjustment of the voltage may have caused some error as we may have not adjusted it to the exact values required. If there were a more detailed and precise knob, it could reduce the error. Also, the wire were very rusty therefore acting as very poor conductors. The obvious solution would be to use newer wires.  

Conclusion:

        The purpose of this lab was to see how the potential difference and the electric current going through a conductor are related. By graphing the results it showed that they were directly proportional. This proved to be correct also for the cold resistivity of the light bulb, however the resistivity of the light bulb after it lit up contradicted Ohm’s law as the resistivity did not remain constant.

...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. Marked by a teacher

    Determining Avogadro's Number Lab

    4 star(s)

    Thus, the average current after 20 minutes is 0.95 A ±10.5%. Time: Time = 60 seconds x 10 minutes Time = 600 seconds Percent uncertainty of time = Percent uncertainty of time 0.833% The percent uncertainty for time is approximately 0.833%.

  2. Peer reviewed

    Measurement of the resistivity of Nichrome

    5 star(s)

    There are several possible sources of error and uncertainty in the experiment. 1. The most likely error might be reading the ammeter and voltmeter. As the voltage and current are always changing, it is hard to read precisely.

  1. Peer reviewed

    Investgating resistivity - Planning and Implementing

    4 star(s)

    For voltage the highest percentage error was therefore And for current the highest percentage error was therefore These errors are quite significant. If they were any greater the value for the resistance calculated from these currents and voltages, and therefore the value of resistivity calculated from that resistance, might be too unreliable.

  2. Finding the Resistivity of a Wire

    However, my graph shows that this was fairly irrelevant, due to the reliability of the line for best fit. o Area of cross-section of wire: I cannot be sure that the wire was cylindrical throughout the wire, which could have affected the resistivity value, though by taking several readings and

  1. Physics - Resistivity

    Voltage can also be where a charge is gaining energy, such as in transformers and generators, this is called an electromotive force. Thus the voltage across the power supply is an electromotive force or e.m.f., while the voltage across a resistor in a circuit (such as a wire or a light bulb)

  2. Choosing a light source

    This also leases to a great risk for the college because then there will be no student's attending the college and the authorities might consider in shutting it down. All of these things would have happen if Leyton Sixth Form College were generating light through e.g.

  1. Characteristics of Ohmic and Non Ohmic Conductors.

    Plastic is an example of a covalent substance. In circuits an ammeter is used to measure the current, which is measured in amps, and it is connected in series always. Amps is a measure of the amount of current flowing through the circuit.

  2. Measuring The Resistivity Of A Pencil Lead.

    From these results I can see that the temperature did not rise and thus affect the results. This tells me that my settings for my investigation should be : 1. Power pack set at 4V 2. Current at 0.1A Method Now I have completed the preliminary work I am able to start my main investigation.

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