List of top Mechanical Engineering Questions on Thermodynamics

Which of the following are intensive properties? A. Kinetic energy
B. Thermal conductivity
C. Pressure
D. Entropy
E. Volume

In modern steam generator, the correct path of gases from boiler furnace to chimney is: A. Boiler furnace
B. Economizer
C. Superheater
D. Air preheater
E. Chimney

Assertion (A): In a power plant working on a Rankine cycle, the regenerative feed water heating improves the efficiency of the steam turbine.
Reason (R): The regenerative feed water heating raises the average temperature of heat addition in the Rankine cycle.

A petrol engine has compression ratio from:

The speed of sound of carbon monoxide (CO) at 200 kPa pressure and 300°C in m/s is: (Properties of CO: molecular weight = 28.01, \(k = 1.4\))

Vapour Absorption Refrigeration System, normally uses refrigerant.

Which of the following is NOT a type of surface steam condenser:

In jet type steam condensers; .

For Parson’s reaction turbine, degree of reaction is .

Which of the following steam turbine is NOT compounded?

A jet of water coming out of a nozzle with a velocity of 20 m/s strikes a hinged plate at the centre. Nozzle area is $2 \times 10^{-3}$ m$^2$; density of water is 1000 kg/m$^3$. If the angle of the swing of the plate from the vertical is $30^\circ$, then the weight of the plate is:

In flow through pipes, according to Darcy-Weisbach formula the loss of head due to friction is proportional to , Where, V = Mean velocity of flow.

Which of the air compressors, is NOT a rotary type compressor?

In a single stage reciprocating air compressor, the work done on air to compress it from suction pressure to delivery pressure will be minimum, when the compression is:

Which of the following device is used to measure the speed of Internal Combustion Engine?

In four stroke internal combustion engine, the period during which both inlet and exhaust valves remain open, is called:

The ratio of brake power to indicated power of an internal combustion engine is called:

Match List I with List II:

LIST I (Component)	LIST II (Equipment used in)
A. Draft Tube	III. Francis Turbine
B. Thermostatic Expansion Valve	II. Cold Storage
C. Feed Water Heater	I. Thermal Power Plant
D. Automatic Expansion Valve	IV. Central AC Plant

Choose the correct answer from the options given below:

Assertion (A): In heating and dehumidification of air, relative humidity of air decreases.
Reason (R): Sensible heating causes enthalpy to decrease.
In light of the above statements, choose the correct answer from the options given below.

In a simple saturated Vapour compression refrigeration cycle, the enthalpy at various state points are: 10 kJ/kg, 45 kJ/kg and 25 kJ/kg. The mass flow rate of refrigerant is 2 kg/s:

1. The power consumption of compressor is 40 kJ/kg
2. The refrigeration capacity is 70 kW
3. The COP is 1.75
4. Heat rejected in condenser is 110 kW

Choose the correct answer from the options given below.

For the same compression ratio and same heat supplied in Otto, Diesel and Dual cycles:
(A) Otto cycle has maximum efficiency.
(B) Diesel cycle has minimum heat rejected.
(C) Dual cycle has maximum heat rejected.
(D) Diesel cycle has maximum heat rejected.
Choose the correct answer from the options given below.

With increase in pressure ratio in Brayton cycle the net work output

A system at 500 K receives 7200 kJ/min of heat from a source at 1000 K The ambient temperature is 300 K The system and source temperature remain constant during heat transfer The decrease in available energy due to heat transfer through finite temperature difference is