https://physlab-wiki.com/ 2026-04-22T13:16:21+00:00 https://physlab-wiki.com/ https://physlab-wiki.com/lib/tpl/UChicago/images/favicon.ico text/html 2021-09-15T17:43:46+00:00 Anonymous (anonymous@undisclosed.example.com) https://physlab-wiki.com/physicsdemos/electricity_and_magnetism/electromagnetic_induction/ac_induction_lights_bulb?rev=1631742226&do=diff AC Induction Lights Bulb A small light bulb connected to a large coil is lit by magnetic induction. A time-dependent magnetic field is generated with another coil which is plugged into a Variac. The brightness of the bulb is dependent on the proximity and alignment of the two coils. One may also observe the brightness of the bulb increase when a ferromagnetic rod is inserted inside the coils. text/html 2025-03-05T10:04:38+00:00 Anonymous (anonymous@undisclosed.example.com) https://physlab-wiki.com/physicsdemos/electricity_and_magnetism/electromagnetic_induction/can_crusher?rev=1741187078&do=diff Can Crusher—Retired A large capacitor is discharged through a small coil resulting in induced current and a magnetic field strong enough to blow a can apart. Video filmed at 5000 frames/second Setup CURRENTLY UNSAFE. DO NOT USE. K3 PIRA DCS 5K20.65 text/html 2021-12-13T14:35:19+00:00 Anonymous (anonymous@undisclosed.example.com) https://physlab-wiki.com/physicsdemos/electricity_and_magnetism/electromagnetic_induction/coupled_oscillating_magnets?rev=1639424119&do=diff Coupled Oscillating Magnets Requirements * Neodymium magnets (x2) * springs (x2) * magnetic coil (x2) * banana cables (x2) * banana to BNC and oscilloscope (optional) Description: Each magnet is attached to a spring (both of which are relatively weak and have equal spring constants) and is positioned so that the equilibrium position of the spring with the magnet attached lies inside a copper coil. The leads of one coil are connected to the leads of the other coil with banana ca… text/html 2021-11-05T18:25:31+00:00 Anonymous (anonymous@undisclosed.example.com) https://physlab-wiki.com/physicsdemos/electricity_and_magnetism/electromagnetic_induction/dc_induction_with_galvanometer?rev=1636151131&do=diff DC Induction with Galvanometer The induced current in a coil is viewed with a galvanometer as the coil is moved relative to a second coil which carries a current from a low-voltage DC power supply. J3, A4, K4 PIRA DCS 5K10.30 text/html 2021-11-05T18:25:52+00:00 Anonymous (anonymous@undisclosed.example.com) https://physlab-wiki.com/physicsdemos/electricity_and_magnetism/electromagnetic_induction/dc_motor?rev=1636151152&do=diff DC Motor All of the working parts of this large, simple DC motor are clearly visible. J3, A4 PIRA DCS 5K40.10 text/html 2021-11-05T18:26:13+00:00 Anonymous (anonymous@undisclosed.example.com) https://physlab-wiki.com/physicsdemos/electricity_and_magnetism/electromagnetic_induction/dissectible_transformer?rev=1636151173&do=diff Dissectible Transformer An electrical transformer with interchangeable coils is driven with a sine generator as the primary and secondary voltages are viewed simultaneously on a projection oscilloscope. J3, A0, scope near workbench or D3 PIRA DCS 5K30.20 text/html 2021-11-05T18:26:35+00:00 Anonymous (anonymous@undisclosed.example.com) https://physlab-wiki.com/physicsdemos/electricity_and_magnetism/electromagnetic_induction/eddy_current_damped_pendulum?rev=1636151195&do=diff Eddy Current Damped Pendulum The motion of aluminum plates swinging through the gap of a permanent magnet is damped due to the creation of eddy currents. Aluminum plates with three different geometries are used to show how constraining the size of the eddy current loops can limit the damping force. text/html 2021-11-05T18:25:02+00:00 Anonymous (anonymous@undisclosed.example.com) https://physlab-wiki.com/physicsdemos/electricity_and_magnetism/electromagnetic_induction/eddy_current_pipe?rev=1636151102&do=diff Eddy Current Pipe A large permanent magnet dropped down a copper pipe takes a very long time to reach the bottom. Magnetic tape attached to the pipe allows the magnet to be located during its descent. B2 top, D3 PIRA DCS 5K20.25 text/html 2021-11-05T18:26:59+00:00 Anonymous (anonymous@undisclosed.example.com) https://physlab-wiki.com/physicsdemos/electricity_and_magnetism/electromagnetic_induction/eddy_current_rolling_cylinder?rev=1636151219&do=diff Eddy Current Rolling Cylinder A hollow, conducting cylinder is propelled by the motion of permanent magnet nearby. J3, D3 PIRA DCS 5K20.xx text/html 2021-12-13T14:44:38+00:00 Anonymous (anonymous@undisclosed.example.com) https://physlab-wiki.com/physicsdemos/electricity_and_magnetism/electromagnetic_induction/electric_monochord?rev=1639424678&do=diff Electric Monochord Requirements * Electric monochord (built) * Amplifier * Oscilloscope Description This demo serves to illustrate both the principle of electromagnetic induction as well as how it is something with which all of us have experience through music. The electric monochord is essentially a one stringed analogue of an electric guitar. It consists of a ferromagnetic string of adjustable tension, a magnet placed underneath the string that slightly magnetizes it, and a ~8500 turn… text/html 2025-07-28T14:57:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://physlab-wiki.com/physicsdemos/electricity_and_magnetism/electromagnetic_induction/electromagnet_spark?rev=1753729069&do=diff Electromagnet Spark A one to two inch spark is produced when the switch of a large electromagnet is opened. Uses the same electromagnet as the sword in the stone demo. Near B3 cabinet PIRA DCS 5J10.30 text/html 2021-11-05T18:27:59+00:00 Anonymous (anonymous@undisclosed.example.com) https://physlab-wiki.com/physicsdemos/electricity_and_magnetism/electromagnetic_induction/homopolar_generator?rev=1636151279&do=diff Homopolar Generator An EMF is generated in a way not described by Faraday's law. A permanent cylinder magnet is positioned inside, and coaxial with, a hollow cylindrical conductor. When the conductor is rotated and the magnet is kept stationary an EMF is generated between two points along the length of the conductor. When the magnet is rotated and the conductor is kept stationary no EMF is generated. When both magnet and conductor are rotated together an EMF is generated. The direction and r… text/html 2025-07-07T14:04:00+00:00 Anonymous (anonymous@undisclosed.example.com) https://physlab-wiki.com/physicsdemos/electricity_and_magnetism/electromagnetic_induction/jumping_ring?rev=1751911440&do=diff Jumping Ring A conducting ring is placed onto the protruding ferromagnetic core of a coil. When an AC current is applied to the coil the ring will fly off of the apparatus. While Lenz's law is often cited as the reason for this behavior, Lenz's law is insufficient to describe the force on the ring. One may show that a ring with a gap will not jump when current is applied. One may also show that a ring cooled with liquid nitrogen will jump much higher than one at room temperature. text/html 2021-11-05T18:28:47+00:00 Anonymous (anonymous@undisclosed.example.com) https://physlab-wiki.com/physicsdemos/electricity_and_magnetism/electromagnetic_induction/magnetic_induction_in_loops_of_wire?rev=1636151327&do=diff Magnetic Induction in Loops of Wire One or multiple loops of a wire are moved through the field of a permanent magnet. The current induced in the wire is shown on a projection galvanometer. K4 PIRA DCS 5K10.15 text/html 2025-07-22T10:04:14+00:00 Anonymous (anonymous@undisclosed.example.com) https://physlab-wiki.com/physicsdemos/electricity_and_magnetism/electromagnetic_induction/magnetic_induction_lights_bulb?rev=1753193054&do=diff Magnetic Induction Lights Bulb A high-strength neodymium magnet is quickly moved in and out of a coil connected to a small light bulb. K4, D3 PIRA DCS 5K10.25 text/html 2021-11-05T18:29:40+00:00 Anonymous (anonymous@undisclosed.example.com) https://physlab-wiki.com/physicsdemos/electricity_and_magnetism/electromagnetic_induction/motor-driven_ac_generator?rev=1636151380&do=diff Motor-Driven AC Generator A motor is used to rapidly rotate a conducting loop in a magnetic field. The sinusoidal output from the coil can be observed with a projection oscilloscope. The strength of the magnetic field, due to a pair of Helmholtz coils, can be adjusted. The speed of the loop rotation can also be adjusted by changing the position of the belt on a step-cone pulley mounted on the motor shaft. text/html 2021-11-05T18:30:11+00:00 Anonymous (anonymous@undisclosed.example.com) https://physlab-wiki.com/physicsdemos/electricity_and_magnetism/electromagnetic_induction/permanent_magnet_through_a_coil?rev=1636151411&do=diff Permanent Magnet Through a Coil A permanent bar magnet is moved in and out of a coil connected to a projection galvanometer. One can observe how the magnitude and direction of the current changes with the direction and velocity of the relative motion. text/html 2021-11-05T18:30:31+00:00 Anonymous (anonymous@undisclosed.example.com) https://physlab-wiki.com/physicsdemos/electricity_and_magnetism/electromagnetic_induction/sword_in_the_stone?rev=1636151431&do=diff Sword in the Stone A copper or aluminum plate dropped or pulled from between the poles of a large electromagnet. large demos area near B0, cart in front of workbench PIRA DCS 5K20.22