Physics.ie - Focus on Physics

Glossary E

East-West effect
The amount of cosmic rays coming from the west is greater
than the amount coming from the east. This is due to fact that
the cosmic rays are mainly positive therefore the positive rays are
deflected by the Earth’s magnetic field. Discovered by Luis Walter Alvarez.
Eclipse
Is when an object moves into the shadow of another.
Lunar eclipse is where the shadow of the Earth falls on the
moon and a Solar eclipse happens when the shadow of
the moon falls on the Earth. [more]
Elastic Limit
Maximum stress that a material can withstand before it is
permanently deformed – once the stress is removed the material
will return to its original shape.
Electron microscope
Is a scientific instrument that uses a beam of highly energetic electrons
to examine objects on a very fine scale. There are two different types
Transmission Electron Microscope and Scanning Electron Microscope.
Electroscope
A device used to detect electric charge. One version is a gold leaf
electroscope in which two leaves of gold are attached to a metal plate,
when a charge is placed on the metal plate the leaves will part
because like charges repel each other.
Epicycle
A circle whose centre rotates about the the edge of another larger circle.
Used by Ptolemy to examine the motion of the planets.
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