School of Physics Lecture Demonstration Manual

Eb-11 Lenz’s Law (Coil).

Published: Tuesday 05 June 2007 - Updated: Tuesday 29 March 2011


To demonstrate the induced E.M.F when there is relative motion between a conductor and a magnetic field.



Click on pictures to enlarge.

Lenz's Law coil pic


Lenz's Law Coil


When a strong magnet is moved back and forth through the coil, one of the two LED’s will light up as the direction of the magnetic field changes. This is dependent on which pole of the magnet enters the coil first. If a north pole of a magnet is moved through the coil one of the LED will light, on removing the coil the other will light. The opposite led lights if the south pole is made to enter the coil.

Safety notes


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