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

Magnetism Investigation

Extracts from this document...

Introduction

Magnetism Investigation PURPOSE To measure the magnetic force between two current-carrying conductors, and calculate the magnetic permability of free space. WHAT'S THE POINT? To see magnetic fields producing a force on a conductor which carries a current. BACKGROUND READING: Cutnell and Johnson, Chapter 21, Sections 5 and 10. INTRODUCTION AND THEORY: When a current I passes through a long, straight conductor, a magnetic field B is created. According to Ampere's law, the magnitude of the field at a perpendicular distance d from the conductor is given by the relation. mu * I B = -------------- 2 * pi * d In SI units the magnetic field is measured in tesla when I is in amperes and d is in meters. The quantity mu is a constant known as the permeability of free space and has the assigned value of -7 tesla * meter mu = 4 * pi * 10 ------------- (1) amp It is assigned this value in order to maintain consistent units when the permittivity of free space has the value associated with Coulomb's law for the electrostatic force between charges, with the additional requirement that the square of the speed of light in a vacuum be given by 1 c = ------------------- (2) sqrt(epsilon * mu) where epsilon is the permeability of free space. ...read more.

Middle

Use care when handling this device even after the experiment is completed. PROCEDURE: 1. The equilibrium separation of the two conductors do should initially be set at a few millimeters. If it is not, very carefully move the counterpoise weight behind the mirror by turning it on its screw. Move the counterpoise weight until the upper bar comes to rest a few millimeters above the fixed bar. 2. You will need to measure the separation between the upper and lower bars. Use the following method, in which the motion of the laser spot shows the motion of the upper bar in a greatly magnified manner. Plug in the laser's power cord so that a red spot appears on the mirror, and its reflection back near the laser itself. Let the upper bar settle in its rest position, a small distance above the fixed lower bar. Note the position of the laser spot on the scale attached to the plastic bar at the far end of the table; we will refer to this as the equilibrium position. Next, place the 500-mg weight gently onto the pan at the center of the upper bar. The bar should sink down on top of the lower bar and stay there. As the upper bar sinks, the mirror tilts and the reflected laser spot sinks, too. ...read more.

Conclusion

In what step of your procedure do you think the largest error occured? Appendix: Magnification Using the Optical Lever We start off with the upper bar and lower bar some distance do apart. When the laser beam reflects from the mirror, it strikes the scale at some point P. Then we weigh down the upper bar so that it tilts by an angle theta and comes into contact with the lower bar. The distance from the knife edges to the end of the upper bar is a, so do tan (theta) = ---- a The mirror attached to the upper bar shares this tilt. The laser beam strikes the mirror at an angle theta and is reflected at an angle theta, so the light is deflected by a total angle 2 * theta and now strikes the scale at point Q. The distance from the mirror to the scale on which the laser shines is b, so we can figure out the distance D between P (the equilibrium location of the laser spot) and Q (the location of the spot when the bars touch). x = b * tan(theta) do = b * ---- a D = distance from P to Q = 2 * x b = 2 * --- * do a If we rearrange to solve for the distance do between the conductors in the equilibrium position, we find D * a do = ------- 2 * b Last modified by MWR 5/2/1999 ...read more.

The above preview is unformatted text

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. Single Phase Transformer (Experiment) Report.

    transformers operating from power stations whose bus voltage must be varied to suit local distribution. In industrial work, it is used for the control of current in a variety of furnace operations and electrolytic processes. It all furnishes a convenient means for voltage regulation of concentrated industrial loads.

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

    Results 2 had a larger value for the cooling correction than graph 3 because the maximum temperature reached was higher and therefore the temperature gradient between the block and the air was greater and therefore more heat is likely to be lost into the surroundings.

  1. Characteristics of Ohmic and non-Ohmic Conductors.

    Experiment 3: In my third experiment, I will be investigating the increase in current, as the voltage increases in a thermistor. The circuit will be connected as shown in the circuit diagram above, and 10 sets of voltage and current will be noted, at intervals of 0.2 V.

  2. Characteristics of Ohmic and Non Ohmic Conductors.

    The resistance does not vary according to the current, it remains constant. The current flowing through it also has to be kept less because then it will lose its property of being an ohmic conductor. The temperature at which the metal is used will change as the current flowing through it.

  1. A2 Viscosity investigation

    The air bubbles can effect the investigation in one of two ways or more commonly both thus making it impossible for me to determine what effect they have had on the investigation. On one hand you could say they would make the syrup appear less viscous as the ball bearings

  2. To find which of the circuits, shown below, are most suitable to measure a ...

    Another issue is heat, as the Power Pack (or Lab Pack) is left on, the temperature of the wires, and the resistors increases, and so, the longer I leave the power pack on for the more inaccurate my results get.

  1. The strength of an electromagnet.

    This was measured using the ammeter and controlled using the variable resistor. The amount of nails lifted was the outcome measure we recorded using the panel pins and the balance. The current was varied to 0.1, 0.3, 0.5, 0.7, 0.9, 1.1, and 1.3 amps and the weight of panel pins lifted at each current was recorded.

  2. Investigating the factors affecting the size of current flowing through a length of resistivity ...

    If therefore the length and cross-sectional area of the putty are both doubled at the same time, there will be no overall change on the size of the current. This can be clearly shown by looking yet again at the results from UNILAB: UNILAB VALUES Expt.

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