Thermodynamic Processes Video Lecture - Physics Class 11 - NEET

thermodynamic processes the physical
quantities which are used to specify the
state of a system are called the
thermodynamic coordinates pressure
temperature and volume are examples of
thermodynamic coordinates whenever there
is a change in the thermodynamic state
of a system we say that the system has
undergone a process the change is taking
place inside the pressure cooker and the
heat engines are examples of
thermodynamic processes did you know
that a thermodynamic process is taking
place inside the body of the african
bombardier beetle when it emits a jet of
defensive spray from the movable tip of
its abdomen
the different types of thermodynamic
processes are isothermal process
adiabatic process isochoric process and
isobaric process
isothermal process isothermal process is
a physical change in which pressure and
volume of a system change at constant
temperature melting at constant pressure
during melting the temperature remains
constant but there is an increase in
internal energy due to change of phase
from solid to liquid boiling at constant
pressure during boiling the temperature
remains constant here there is an
increase in internal energy due to the
change of phase from liquid to wait the
state isothermal process is slow there
is exchange of heat between the system
and the surroundings if the system is
enclosed in a cylinder having conducting
walls when the system expands heat is
absorbed when it is compressed heat is
rejected in an isothermal process in
general none of the quantities Delta Q
Delta W or Delta U is zero where Q is
the heat energy W is the work done and U
is the internal energy equation for
isothermal for an isothermal process T
is constant so PV is equal to a constant
the variation of B with V is as shown
here
adiabatic process adiabatic process is a
physical change in which the pressure
volume and temperature change examples
for adiabatic processes are the sudden
explosion bursting of a bus tire and the
compression stroke in an internal
combustion engine there is no exchange
of heat between the system and the
surroundings so Delta Q is equal to zero
heat can be prevented from entering or
leaving the system by performing the
process quickly the flow of heat
requires a certain time so any process
performs suddenly will be adiabatic to
prevent the heat flow the system is
perfectly insulated from the
surroundings by using known conductors
of heat like asbestos and cork during
expansion work is done by the system and
hence it gets cooled during compression
work is done on the system and hence it
gets heated up equation for adiabatic
process is PV raised to gamma is equal
to a constant where gamma is the ratio
of the two specific heat capacities of
the gas during this process no heat
enters or leaves the system so Delta Q
is equal to 0 substituting the value of
Delta Q in Delta Q is equal to Delta u
plus Delta W 0 is equal to Delta u plus
Delta W therefore Delta W is equal to
minus Delta u this means for doing work
internal energy is used negative sign
shows that when work is done by the
system its internal energy decreases
you