2. The transmission of heat from places of higher
to places of lower temperature in a substance.
The
reciprocal
of
the
resistivity
or
specific
re-
sistance of a conductor.
A
body
capable
of
carrying
an
elecnic
current.
A
red
metal.
It
is
unaffected
by
water
or
steam.
6.
7. White, mther soft metal. The best-known con-
ductor of electricity.
A
physiological
sensation
received
by
the
ear.
It is caused by a vibmting source and nansmit- ted as a wave motion through air.
10) Titles.- Elecnic Field; Direct Current; Alternating Current; Elecno- magnetic Radiation ; Continuous Wave; Elecnomagnetic Spectrum.
ciated with elecnic and magnetic fields. This
radiation is emitted by matter in units called photons.
magnetic radiations are propagated. The lowest bequencies are radio waves, increases of be- quency produce infrared radiation, light, ultra- violet radiation, X-rays, gamma-rays and fi- nally the radiation associated with cosmic rays.
3. Radio or radar transmissions which are gener-
ated continuously and not in short pulses.
4. An electric current flowing always in the same
Direction.
A
flow
of
elecnicity
which,
after
reaching
a
maximum in one direction, decreases, finally reaching a maximum in the opposite direction, the cycle being repeated continuously. The number of such cycles per second is the fre- quency.
6. The region near an electric charge, in which a
force is acting on a charged particle.
ffJ titles: Energy; Elecnical Energy; Chemical Energy; Radiant Energy; Kinetic Energy; Potential Energy.
1. The capacity for doing work.
2. That part of the energy stored within an atom or
molecule which can be released by a chemical
3. The energy which a body possesses by virtue of
its position. It is measured by the amount of work the body performs in passing born that position to a standard position in which the en- ergy is considered to be zero.
4. The energy which a body possesses by virtue of
The
energy
that
is
transmitted
i»
the
form
of
radiation.
6. The energy associated with elecnic charges and
their
movements.
It
is
measured
in
watt
sec-
onds
(joules)
or
kilowatt-hours.
Device
for
producing
an
electric
current
by
chemical reaction.
tricity. An elecnic current is passed between two plates in a liquid; this causes chemical changes in the plates and the liquid. When the changes are complete, the device is charged.
Semiconductor
devices
which
are
made
from
thin slices of silicon. Almost all Russian and American satellites have used such cells to supply on-board electrical power. Although the efficiency of these cells is no more than l0•z'«, they provide a reliable elecnic power source that lasts for years on a satellite.