Chapter 11 applying electromagnetism.

What is an electrostatic generator?

An electrostatic generator is a device that produces static electricity.

What is the most common type of electrostatic generator?

The most common electrostatic generator in use today is the high voltage Van de Graaff generator.

What causes lightning during thunderstorms?

The large amount of discharge of static electricity between the ground and a cloud during a thunderstorm causes lightning.

What is a device used to protect buildings from lightning strikes?

A modest device for protecting buildings and other structures from lightning strikes is a lightning rod.

What is St. Elmo's fire?

St. Elmo's fire is an eerie bluish glow that sometimes appears around pointed objects during storms.

What is a Leyden jar?

A Leyden jar is an early foil-lined device used to store electric charge.

What is a capacitor?

A capacitor is a device used to store static electric charge.

What is xerography?

Xerography is an electrostatic method of reproducing images on paper, used in devices such as printers, air filters, and car paint.

How does an incandescent lamp produce light?

An incandescent lamp produces light by heating a thin piece of wire or filament to a very high temperature.

How does a fluorescent lamp work?

A fluorescent lamp produces light by passing electrical current through a long tube filled with a low pressure mixture of mercury vapor and argon.

What are compact fluorescent lamps?

Compact fluorescent lamps are coiled tubes about the size of a regular incandescent bulb.

What is a neon lamp?

A neon lamp is an electrical discharge lamp filled with neon gas instead of mercury vapor.

What are light-emitting diodes (LEDs)?

Light-emitting diodes, or LEDs, are semiconductor devices that emit light when a direct electric current is applied.

What is a solenoid?

A solenoid is a wire coil with an iron rod free to slide back and forth.

What does a telegraph consist of?

A telegraph consists of a switch or key at one end of a long wire and an electromagnet at the other end.

What is a relay?

A relay is an electrical switch operated by an electromagnet.

How does a loudspeaker function?

A loudspeaker converts pulses of electricity into sound waves.

How does a DC motor operate?

A DC motor works using the attraction and repulsion of magnetic poles with an electromagnet called the armature mounted on a rotating shaft.

What is the function of a commutator in a DC motor?

The commutator reverses the current in the armature every half-turn, keeping it rotating continuously.

What is the difference between AC and DC motors regarding current reversal?

An AC motor does not need a commutator because alternating current already alternates direction.

What is a battery?

A battery consists of one or more electrochemical cells connected to provide a single source of current.

What is electromagnetic induction?

Electromagnetic induction is the ability to convert magnetism to mechanical motion into electric current.

What does a generator do?

A generator uses electromagnetic induction to produce electricity.

What is the structural similarity between motors and generators?

AC and DC generators are structurally the same as AC and DC motors, but a motor converts electrical energy to mechanical energy while a generator does the inverse.

What is a magnetohydrodynamic generator?

A magnetohydrodynamic generator conducts fluid which passes through a magnetic field at high speed.

What does a transformer do?

A transformer increases or decreases the voltage of alternating current using electromagnetic induction.