10. Faraday’s Law of EM induction

Experiment 10: Faraday’s Law of Electromagnetic Induction Theory Faraday's Law of electromagnetic induction tells us that changing magnetic flux Φ B through the surface bounded by the closed circuit induces emf E in this circuit . Mathematically, this law states : E = | ∆Φ B ∆t | (1) where magnetic flux is defined as Φ B = BA cos ϕ (2) In Eq. (2), B is the magnetic field, A is the area of the surface magnetic flux passes through, and ϕ is an angle between direction of magnetic field and the normal line to the surface: In this lab, we’ll check Eqs. (1) and (2) experimentally. Procedure Physics Simulations: Faraday's Law https://www.geogebra.org/m/WjtWQbgC

Experiment Part A. Changing Magnetic Field 1. Choose variable “Variation of the magnetic field”. 2. Set the range of changing magnetic field B from +5T to -5T and measure the induced emf E . Record the result in the data table. 3. Repeat your measurements of E as you decrease the magnetic field range by 0.5 Tesla and record your data in the data table 4. Calculate E using Eqs. (1) and (2) and record your theoretical results in the data table. Note : the radius of the circular wire loop in part A is 3m; time of experiment is 5s. Range of B 5 T 4.5 T 4 T 3.5 T 3 T 2.5 T E , exp. 56.5 50.89 45.24 39.58 33.93 28.27 E , theor. 56.5 50.87 45.22 39.56 33.91 28.26 Part B. Changing the area of the wire loop 1. Choose variable “Radius of the loop”. 2. Set the radius of the circular wire loop to be 5m and measure the induced emf E . Record the result in the data table. 3. Repeat your measurements of E as you decrease the radius by 0.5 meters and record your data in the data table 4. Calculate E using Eqs. (1) and (2) and record your theoretical results in the data table. Note : magnetic field in part B changes from +5T to -5T; time of experiment is 5s. Radius 5 m 4.5 m 4 m 3.5 m 3 m 2.5 m E , exp. 157.08 127.23 100.53 76.97 56.55 39.27 E , theor. 160.22 129.77 102.54 78.50 57.67 40.05 Part C. Changing the angle θ between the field and the surface 1. Choose variable “Angle between the field line and the surface”.

3. In part C experiment, was the magnetic flux Φ B increasing, decreasing or staying the same when angle θ was increasing? Explain your answer. The magnetic flux was increasing as the angle was increasing because of the direction it pointed towards.