Physics 2225: Faraday’s Law Purpose Study the induction of electric current according to Faraday’s Law.

Physics 2225: Faraday’s Law Faraday’s Law Induced electromotive Force (“voltage”) Change in the magnetic flux through the loop Time interval over which the flux change occurs.

Physics 2225: Faraday’s Law Magnetic Flux Through a Loop of Wire Cross sectional area of the loop B

Physics 2225: Faraday’s Law An Example of Induced Voltage  B  B Time it took to rotate coil by 90  :  t

Physics 2225: Faraday’s Law Activity 1: Flux Change by Moving Magnet LED Plug LED connector into 2000 turn detector coil LED light turns green or red, depending on the polarity of the voltage.

Physics 2225: Faraday’s Law Activity 1: Flux Change by Moving Magnet Cow magnet Move cow magnet EXTREMELY QUICKLY in and out of the detector coil. Watch color of LED during movement.

Physics 2225: Faraday’s Law Activity 2: Flux Change Using Function Generator Function Generator 200 turn field coil: Called “field” coil because it is used to generate a magnetic field by running current through it. An alternating current (from function generator) creates an alternating magnetic field by this coil.

Physics 2225: Faraday’s Law Activity 2: Flux Change Using Function Generator: Setup BNC T-piece Signal generator output BNC to Banana adapter “Banana” cables Ch 1: Monitors signal from signal generator (and thus the B-field generated by the field coil). Ch 2: Monitors the voltage induced in the detector coil. Now you can compare these two on the two oscilloscope channels Don’t use middle connector

Physics 2225: Faraday’s Law Activity 3: Replacing Field Coil with Small Coil Signal generator output

Physics 2225: Faraday’s Law Activity 4: Flux Change by Moving Magnet, Observed with Oscilloscope Plug both BNC cable and LED into the detector coil Similar to Activity 1, but also monitor voltage with Ch. 1 of oscilloscope. Set timescale to 500ms, vertical scale as needed.