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Mechanical Engineering - MCQ Practice Questions

Core mechanical MCQs — thermodynamics, SOM, fluid mechanics for GATE & PSUs.

259 questions | 100% Free

Q.1Easy

Which of the following is an intensive property in thermodynamics?

Q.2Easy

The First Law of Thermodynamics is a statement of conservation of:

Q.3Easy

For an ideal gas undergoing an isothermal process, the change in internal energy is:

Q.4Easy

The entropy of a reversible adiabatic process is:

Q.5Easy

Which process requires zero work to be done by the system?

Q.6Medium

A heat engine operating between two temperature reservoirs has a maximum theoretical efficiency given by:

Q.7Medium

In a throttling process (Joule-Thomson expansion), the enthalpy of the fluid:

Q.8Medium

The availability or exergy of a system is zero when the system is in:

Q.9Medium

For a real gas, the compressibility factor Z is defined as:

Q.10Medium

The polytropic process for an ideal gas follows PV^n = constant. When n = 0, the process is:

Q.11Medium

In a closed system, the total energy balance equation for a time interval is:

Q.12Medium

Two bodies at different temperatures are brought into contact in an isolated system. The total entropy of the system will:

Q.13Medium

The specific heat capacity at constant volume (Cv) for a monatomic ideal gas is:

Q.14Medium

In a vapour compression refrigeration cycle, the throttling device (expansion valve) causes:

Q.15Hard

A Carnot refrigerator operates between T_H = 300 K and T_C = 250 K. Its coefficient of performance (COP) is:

Q.16Hard

The Clausius-Clapeyron equation relates vapor pressure to:

Q.17Hard

For a system undergoing a reversible process from state 1 to state 2, which statement is true?

Q.18Hard

In a turbojet engine operating on a Brayton cycle, if the pressure ratio r_p increases, the thermal efficiency:

Q.19Hard

Maxwell relations are derived from the equality of:

Q.20Hard

In an Otto cycle engine with compression ratio r = 9 and γ = 1.4, the thermal efficiency is approximately: