Isothermal process.
The process in which the temperature of the system remain constant is called isothermal process.
. In this process heat reservoir is used in order to maintain the temperature of system H. R may behave H. T. R or L. T. R.
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Consider the given figure im which are ideal gas is inclosed and the system is pressed on the heat reservoir when the load placed on the piston is released then expansion takes place in it due to which the internal energy as well as the temperature of the system get reduced but this reduced energy is provided to the system by heqt reservoir in this way the internal energy as well as the temperature of system remain constant.
. In this process the charge in internal energy is i. e Δu = 0
. Now by using the equation of 1st law of thermodynamics we have.
ΔQ = Δu + Δw. .•. Δu = 0
ΔQ = 0 + Δw
ΔQ = Δw
. Above is an equation for isothermal expansion.
. When the compression takes place then amount of heat is released by the system and the work is done on the system in this case the equation for isothermal compression is given by .
-ΔQ = -Δw
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. In this process
. The amount of heat energy is either absorb by the system or released by the system i. e ΔQ = ± .
. The work is done on the system or by the system i. e Δw = ± .
. The amount of internal energy remains constant Δu = 0.
. In this process boyle's law is valid because temperature is constant and v directly proportional 1/p. Vα 1/p
Graph of isothermal process.
. The graph of isothermal process is known as isotherm and it is a curved line.
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