Correct Answer - Option 3 : Change in enthalpy
Explanation:
The first law of thermodynamics:
This law states that the heat and mechanical work are mutually convertible. According to this law, a definite amount of mechanical work is needed to produce a definite amount of heat and vice versa.
∴ From 1st Law of Thermodynamics,
- q = Δu + pdv for a closed system and,
- q = Δh - vdp for an open system
and for a reversible adiabatic process q = 0, .i.e. Δh = vdp
from Steady Flow Energy Equation S.F.E.E
\(\left( {{h_1} + \;\frac{{v_1^2}}{2} + g{z_1}} \right) + q =\;\left( {{h_2} + \frac{{v_2^2}}{2} + g{z_2}} \right) + w \)
when potential and kinetic energy changes are zero or negligible,
h1 + q = h2 + w
given reversible adiabatic process so q = 0,
w = h1 - h2 = Δh
∴ In a steady flow reversible adiabatic process, work done is equal to change in enthalpy.
