• 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...


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


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


  • 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)







Current (mA + 0.01mA)







Potential Difference (V + 0.001V)







...read more.




Resistor 2 = 1.202 KΩ

Resistor 7 = 5.07 KΩ

Light Bulb

Before lighting up:

Voltage (V+ 0.0001V)






Current (mA+ 0.01mA)






The light bulb lit up at:

Voltage (V+ 0.0001V)


Current (mA+ 0.01mA)


After lighting up:

Voltage (V+ 0.0001V)




Current (mA + 0.01mA)




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.


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.  


        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 charge is approximately 570 C ±11.3%. Total charge = Sum of all 3 average charges Total charge = 540 C + 480 C + 570 C Total charge = 1590 C Absolute uncertainty of total charge = Absolute uncertainty of total charge = 192.51 The total charge is 1590 C ±192.5 C.

  2. Peer reviewed

    Measurement of the resistivity of Nichrome

    5 star(s)

    From Wikipedia, I have found the electrical resistivity of Nichrome at room temperature is 1.08 × 10-6?·m, which is very near to the value I have got. However, it is still likely to be a bit higher than expected. Hereunder is the uncertainty and error analysis As Nichrome is an alloy, the resistivity won't be affect much by temperature.

  1. Peer reviewed

    Investgating resistivity - Planning and Implementing

    4 star(s)

    To prevent this, the current and voltages must not be allowed to fall below 0.2, and be kept as high wherever possible. The error in the diameter is, at the very most, 0.005mm. This means the error in the diameter is However, this value is squared in calculating the area,

  2. Finding the Resistivity of a Wire

    1 2 3 Original Reading: 0.91 0.91 0.90 Reading at 90° to Original: 0.91 0.89 0.88 Having completed the practical part of the investigation, these are the tables of results. All measurements are to a measurable degree of accuracy: Length of wire used (metres, ±0.001)

  1. Physics - Resistivity

    The relevant property of the material is its resistivity. VOLTAGE AND CURRENT VOLTAGE Voltage is the 'push' which makes a current flow through a wire. We can distinguish between two types of voltage, one being a voltage where the charge is losing energy, such as through a resistor on the wire like a light bulb, this is called a potential difference.

  2. Measuring The Resistivity Of A Pencil Lead.

    I will start the experiment by setting up the apparatus as shown in my diagram. Once the apparatus is set up I will sharpen the pencil at both ends to its first length. I will then place the crocodile clips on the exposed pencil lead and switch on the power pack.

  1. Choosing a light source

    from my result above, I will be testing my graph to see whether it obeys inverse square law. In order to find out I will be doing some calculations. Looking at the light metre and taking the point, i.e. where the light metre's brightness is 300 lux Now look at

  2. Characteristics of Ohmic and Non-Ohmic Conductors.

    Glass atoms, on the other hand, offer considerable resistance to electrical current because a larger number of their electrons are not free to move from atom to atom. The resistance of a material varies according to its: 1. Length - resistance increases with length because when the electrons travel further,

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