LESSON
OBJECTIVE

Understand that (thermal) energy is
transferred from a region of higher
temperature to a region of lower temperature

Understand that regions of equal
temperature are in thermal equilibrium
Heat Transfer
•
Heat flow between touching objects from hot
region to cold region (High temperature region to
low temperature region)
•
Definition: heat flow is the energy transferred (thermal
energy) from one body to another with some temperature
difference.
•
Thermal Equilibrium
Definition: Thermal equilibrium exists between two
objects if there is no temperature difference or heat
flow between both objects, kept in contact with each
other.
Mode of Heat
Transmission
•
Conduction (In solids)
•
Convection (In liquid and gas)
•
Radiation (In free space or vacuum)
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Summary
•
We have covered the topic of Thermal
Equilibrium and revisited the three main
methods of heat transmission.
LESSON
OBJECTIVE

Understand that a physical property that
varies with temperature may be used for the
measurement of temperature and state
examples of such properties, including the
density of a liquid, volume of a gas at
constant pressure, resistance of a metal,
e.m.f. of a thermocouple
LESSON
OBJECTIVE

Understand that the scale of thermodynamic
temperature does not depend on the property
of any particular substance

Convert temperatures between kelvin and
degrees Celsius and recall that T / K = θ / °C +
273.15

Understand that the lowest possible
temperature is zero kelvin on the
thermodynamic temperature scale and that this
is known as absolute zero
Temperature
scale
 Many
physical properties vary with
temperature

Density of a liquid

Volume of a gas at constant pressure

Resistance of a metal

E.m.f. of a thermocouple
How does liquid
density vary with
temperature?
•
Density decreases when temperature of liquid
increases
•
So, Density of liquid is inversely proportional to
temperature
How does volume
of gas affect
temperature under
constant pressure?

Try to apply charle’s law, PV/T

It is obvious from the relationship,
volume of gas is directly proportional to
the temperature of the gas
How does resistance
of metal change with
temperature?
•
When resistance across a metal increases, the metal
will start feel hot which indicates that the temperature
increases.
What is a
thermocouple?
•
A type of practical thermometer
•
A difference in temperature at both junction will
cause a small EMF to form which will be shown
on the sensitive voltmeter.
Thermocouple vs
Thermistor
Thermodynamic scale
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