Page 50 - Digital Book Bilingual Perpindahan Kalor
P. 50
s u m m a r
s u m m a r y y
1.Heat transfer is the flow of thermal energy from a region
of higher temperature to a region of lower temperature.
This transfer occurs only when there is a temperature
difference.
2.There are three modes of heat transfer:
a. Conduction
Heat is transferred through molecular vibrations
without any bulk movement of matter.
This process occurs mainly in solids.
b. Convection
Heat is transferred through the motion of a fluid (liquid
or gas) caused by differences in density.
c. Radiation
Heat is transferred without the need for a medium, in
the form of electromagnetic waves.
Radiation can propagate through a vacuum.
3.Metals are good conductors of heat because they contain
free electrons that can move easily and carry thermal
energy, whereas most non-metals are good thermal
insulators.
4.Hot liquids or gases have a lower density than cooler
ones. This difference in density causes convection currents
to form.
5.Shiny and light-colored surfaces (such as white) reflect
infrared radiation effectively but are poor absorbers and
emitters of heat.
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