Coil Experiment

Aim: To determine the effect of relative motion between the coil and the magnet is on the induced current (Prac 1)
Hypothesis: The faster the movement between the coil and the magnet, the more current will be produced.
  * coil
  * centre-reading Galvanometer
  * Bar Magnets
  * Connecting Wires x2
  * Alligator clips x2
  1. Collect equipment and set it up like shown in fig. 1 making sure that the galvanometer is connected to the coil with 2 wires.
  2. Hold a magnet stationary inside of the coil and observe the movement of the Galvanometer and record in a table.
  3. Push the North Pole of the magnet back and forth into the coil at a slow speed and record the amount of current produced in the galvanometer.
  4. Repeat steps 3 again but alter the speed of the magnet entering the coil to medium constant speed t and then again with a fast constant speed by altering the movement of the hand
  5. Repeat the experiment three times to achieve consistent results, avoiding outliers and take the averages of results.
Fig.1 – setting of the equipment


Results: Current produced by pushing one magnet bar 7.5cm inside the coil
Speed of the relative motion (movement of magnet) | Current produced (µA) |
| Trial 1 | Trial 2 | Trial 3 | Average |
stationary | 0 | 0 | 0 | 0 |
slow | 2 | 2 | 2 | 2+2+2/3 = 2 |
medium | 14 | 16 | 15 | 14+16+15/3 = 15 |
fast | 32 | 28 | 30 | 32+28+30/3 = 30 |

The results show that the relative motion of the magnet to the coil has an effect on the generated electric current. The faster the motion of the magnet bar, the higher the electromotive force resulting in a higher induced current. Looking at the results, the highest current produced is from the relative speed that is fast which produced 30 µA. The lowest current produced was when the relative speed was slow which produced 2 µA. The medium relative motion of the magnet produced an average 15 µA. Therefore the...