Question

In a steady state process, which of the following quantities remains constant throughout the process?
A) Enthalpy
B) Entropy
C) Temperature and heat both.
D) Internal energy.

Answer 1

Hint:A large number of molecules compose any bulk device. Internal energy is essentially the sum of these molecules' kinetic energy and potential energy. A body's temperature is related to its average internal energy, not to its centre of mass’s kinetic energy of motion.

Complete step by step answer:
A constant state is a state in which, over time, the thermodynamic variable does not change. In the case of problems with heat transfer, if there is a particular rate of heat transfer through the medium(for conduction or convection) and it is stated to have steady-state heat transfer if it stays constant at any time. There may be distinct temperatures in the body at various locations in a steady-state, but the temperature will remain constant at any given point. If the temperature is the same in all places, then it is uniform.

The sum of internal energy stays constant during the process in a steady-state process. The enthalpy $H$of the thermodynamic system is defined as the sum of its inner energy $U$ and the work required to achieve its pressure and volume: \[H = U + PV\], where $P$ is pressure, and $V$ is the volume of the system.
Generally, entropy is described as a measure of randomness or disorder of a system.

Properties of Entropy
-It is a thermodynamic function.
-It is a state function. It depends on the system's condition and not the direction that is followed.
-It is expressed by $S$ but is expressed by ${S^ \circ }$ in the standard state.

In an isolated system, the greater disorder is seen, because entropy often increases. Entropy is also improved as chemical reactions occur if reactants split into more materials. A system has greater randomness at higher temperatures than a system at a lower temperature. It is evident from these examples that entropy increases with a reduction in regularity.

Temperature refers to a body's warmth or coldness. Specifically, this is the manner in which the kinetic energy of particles inside an object is calculated. Particle movement is faster; the temperature is higher and vice versa.
The transfer of thermal energy between molecules within a system is represented by heat and is measured in Joules. It is possible for an object to gain or lose heat, but it cannot have heat. Heat is not a property that an entity or device owns, but rather a measure of change.

From all these observations we can say, in the steady-state process internal energy remains constant.

Thus, the correct option is (d).

Note:
-Internal energy of a system depends upon the parameters like a number of moles, pressure, volume, the temperature of the system.
-When the temperature of a system increases, the internal energy is positive
-When the temperature of the system decreases, the internal energy is negative.