Global Journal of Science Frontier Research, A: Physics and Space Science, Volume 22 Issue 1

b) Appendix B: Sample Charts c) Appendix C: Pre-experiment i. Research question The research question that guides the focus of this writing is: To what extent does increasing the temperature of a coil of wire in a changing magnetic field affect the braking effect produced by eddy currents? In the next section, the hypothesis regarding the phenomenon studied is formulated. ii. Hypothesis According to Faraday's law, if a current-carrying coil is in a magnetic field, a voltage or emf will be induced in it, which in turn produces currents whose magnetic fields oppose the change in the initial magnetic field. The system voltage will be the sum of the absolute values of the induced emf and the potential difference between the system terminals. Consequently, the induced and initial currents will also add up. But, if the temperature of the coil is also increased, the resistance of the wire will increase due to its positive temperature coefficient. Given the inversely proportional relationship between current and resistance, the sum of the absolute values of the currents will decrease. Since the electromagnetic damping force is proportional to the induced current, a decay in this force will be observed, in comparison with scenario in which the coil is not heated. iii. Variables a. Constants • Length, weight and elastic constant of the spring. • Position and holding force of the magnet. • Length, diameter, material and number of turns of the coil, in addition to its position. • The initial push that initiates the oscillating motion. • The initial distance between coil and spring. b. Dependent variables • Braking force. • Amplitude and frequency of the oscillation. c. Independent variable • Coil temperature. iv. Materials • Stainless soft spring • Hollow Coil Of Copper Wire • Ferrite magnet • Grain scale (± 0.0005g) • Ruler (± 5 × 10 -4 m) • Laboratory stand • Digital stopwatch (± 0.001 s) • Heating plate • Infrared thermometer (± 273 K) • 2 three-pointed tweezers with clip • Video Tracker Analysis Program • Variable resistor Relationship between Temperature and the Holding Force of an Electromagnet in a Changing Magnetic Field 1 Year 2022 27 © 2022 Global Journals Global Journal of Science Frontier Research Volume XXII Issue ersion I VI ( A ) Figure 11: Scatter plot for the raw data of the variation of voltage versus temperature