Test: Basic Concept - 1 - Mechanical Engineering MCQ

Thermodynamic cycle can be defined as a series of state changes such that the final and initial state is identical.

In thermodynamics, a system is any part of the universe which is under observation  and the rest of the universe, except the system, are called its surroundings.

So, universe = system + surroundings.

The properties which are mass independent are intensive properties and those which are mass dependent are extensive properties.
Volume depends upon the amount of matter present in the system. Hence, it is an extensive property.

Since heat transfer is the path function hence it is not the property of the system.

Explanation:

- Enthalpy is defined as the heat content of a system at constant pressure. It is represented by the symbol H.

- The unit of enthalpy is derived from the units of energy, which are Joules (J) in the International System of Units (SI).

- The fundamental unit of energy is Joule, which is represented as ML²T^-2.

- Since enthalpy is a form of energy, the fundamental unit of enthalpy is also ML²T^-2.

Open system: Both mass and energy transfer takes place
Closed system: No mass transfer, energy transfer may takes place
Isolated system: Neither energy nor mass transfer takes place.

A system said to be in thermodynamic equilibrium with surrounding if:

It is in thermal, chemical as well as mechanical equilibrium with the surrounding.

And when system is in thermodynamic equilibrium there won't be any spontaneous change.

For reversible process, by first law

For steady flow reversible process,

Since the kinetic energy of the molecules won’t change in vacuum, ⇒ temperature remains constant.