is
placed in an environment with ambient temperature
the
temperature of the hot body falls at a rate proportional to the
temperature difference between it and it's surroundings:
A Level Physics Notes: Thermal Physics and Gases – Newton's Law of Cooling
Newton's Law of Cooling states that if a body initially at
temperatureis
placed in an environment with ambient temperaturethe
temperature of the hot body falls at a rate proportional to the
temperature difference between it and it's surroundings:
The minus sign indicates that
is
decreasing.
This equation can be solved to find the temperature of the hot
body as a function of time.
Example: A body with an initial temperature
is
placed in an environment with ambient temperature
If
after 1 hour the body has cooled to a temperature of
find
and
the time for the temperature to fall to
is higher than the initial temperature of the body,
.
In this case we obtain