Added almost 7 years ago | 00:00:57 | 40946 views
An RF transmitter is connected to a long antenna, emitting radio waves. A dipole antenna with a light bulb between its elements acts as the receiver. When the receiving antenna is parallel to the transmitter, the radio waves are absor...
Added 7 years ago | 00:01:14 | 35439 views
A polarized microwave emitter and a polarized microwave receiver face each other on a table. At first, the emitter and receiver are polarized in the same direction (up-down), and all the emitted signal gets received. When a metal comb i...
Added 7 years ago | 00:02:11 | 27847 views
A double-horn microwave emitter faces a microwave receiver. The receiver is also connected to a speaker, which displays the received signal as audio, and an oscilloscope, which displays the signal visually. When the receiver is moved ...
Added 7 years ago | 00:01:07 | 37095 views
A mass on a spring is driven by a large geared motor apparatus, and exhibits resonance at the appropriate frequency. Below resonance, the driving motion is in phase with the motion of the mass. At resonance the mass is 90 degrees out of...
Added 7 years ago | 00:00:47 | 50704 views
A variable capacitor (C), large inductor or solenoid (L), and 200W light bulb (R) are connected in series to 120 VAC. The inductance of the inductor can be varied by inserting an iron core, and the capacitance can be varied by a row of ...
Added 7 years ago | 00:01:11 | 41779 views
A solid copper pendulum is mounted between the poles of an electromagnet (solenoid). The pendulum is set into motion, and then the magnets are turned on. The magnets induce eddy currents in the copper which oppose the motion of the pe...
Added 7 years ago | 00:01:01 | 32068 views
One wire coil is connected to a radio, and another is connected to a speaker. The two coils are not connected to each other. The radio signal is transmitted through the induced magnetic field caused by the current in the wires. The s...
Added 7 years ago | 00:00:36 | 50733 views
A solenoid enclosed in another solenoid is connected to a 12 volt battery. Also contained in the circuit is an iron contact switch connected to a spring arm, with a gap on one side of it. When the circuit is closed, the inner solenoid a...
Added 7 years ago | 00:01:26 | 49659 views
A solenoid is connected to AC power. First, a 10,000-turn coil is placed over the solenoid, but is not connected to the power source. However, the solenoid still induces current in coil, creating very high voltages because of the high...
Added 7 years ago | 00:00:23 | 64608 views
A large solenoid is connected to DC power through a knife switch. When the switch is closed, the current builds up to approximately 30 amps. When the switch is opened, the solenoid attempts to keep the current flowing, creating a huge...
Added 7 years ago | 00:01:40 | 48807 views
A solid metal ring is placed on an iron core whose base is wrapped in wire. When DC current is passed through the wire, a magnetic field is formed in the iron core. This sudden magnetic field induces a current in the metal ring, which i...
Added 7 years ago | 00:00:29 | 49210 views
Two bar magnets of the same size are dropped through an aluminum tube and a glass tube. The magnet dropped in the glass tube falls at the normal rate of acceleration due to gravity, but the magnet falling through the metal tube is slow...
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