Mechanical Engineering - MCQ Practice Questions
Core mechanical MCQs — thermodynamics, SOM, fluid mechanics for GATE & PSUs.
259 questions | 100% Free
A heat engine operates between temperature reservoirs of 500 K and 300 K. What is the maximum possible efficiency of this engine?
In a diesel engine, if the cutoff ratio is 1.5 and compression ratio is 16, calculate the thermal efficiency. (Assume γ = 1.4)
What is the first law of thermodynamics in differential form?
A piston-cylinder device contains 0.5 kg of steam at 200°C. Heat is removed and the steam condenses to saturated liquid at the same temperature. The latent heat of vaporization at 200°C is 1941 kJ/kg. Calculate heat removed.
In the Rankine cycle, which process involves expansion in a turbine?
What is the relationship between specific heats C_p and C_v for an ideal gas?
A reversible adiabatic process for an ideal gas is also known as:
In a gas turbine Brayton cycle, air enters the compressor at 300 K and 100 kPa. The pressure ratio is 8. If γ = 1.4 and R = 287 J/kg·K, find the compressor outlet temperature (assuming isentropic compression).
Which of the following processes is impossible according to the second law of thermodynamics?
What is the dryness fraction (quality) of steam at a state where internal energy u = 2400 kJ/kg, u_f = 1317.3 kJ/kg, and u_fg = 1753.7 kJ/kg?
In a polytropic process PV^n = constant, if n = 1, the process is:
A Carnot heat pump operates between 270 K and 330 K. If 1000 J of work is supplied, how much heat is delivered to the hot reservoir?
Which thermodynamic property is NOT a state function?
In an Otto cycle, the compression ratio is 10 and γ = 1.4. Calculate the thermal efficiency.
A gas undergoes an isobaric process. If 500 J of heat is added and the gas expands such that work done by the gas is 200 J, what is the change in internal energy?
At what condition is the specific heat capacity at constant pressure equal to infinity?
Which of the following has the highest specific heat capacity among common substances at room temperature?
In a constant volume process, 300 J of heat is removed from a gas. Calculate the work done and change in internal energy.
A heat engine receives 2000 J from a hot reservoir and rejects 1200 J to a cold reservoir. What is the thermal efficiency and work output?
A reversible heat engine operates between two thermal reservoirs. If the temperature of the hot reservoir is 500 K and the cold reservoir is 300 K, what is the maximum possible efficiency of this engine?