Explore topic-wise MCQs in Mechanical Engineering.

This section includes 463 Mcqs, each offering curated multiple-choice questions to sharpen your Mechanical Engineering knowledge and support exam preparation. Choose a topic below to get started.

101.

Compounding                      efficiency at low speed.

A. decrease
B. increase
C. maximizes
D. none of the mentioned
Answer» C. maximizes
102.

Reaction turbine works with the force obtained from change in pressure energy.

A. true
B. false
Answer» B. false
103.

A turbine having alternate blades and nozzles is called as

A. impulse turbine
B. reaction turbine
C. impulse & reaction turbine
D. none of the mentioned
Answer» B. reaction turbine
104.

In condensing turbines vacuum is obtained by

A. sudden pressure drop
B. removal of non condensable gases
C. sudden drop in pressure and by removal of non condensable gases
D. none of the mentioned
Answer» D. none of the mentioned
105.

In velocity compounding the steam is expanded from the boiler pressure to condenser pressure in one set of stationary blades on nozzle.

A. true
B. false
Answer» B. false
106.

Which statement about impulse turbine is true?

A. steam expands over blades
B. steam expends completely in stationary nozzels
C. steam expends partially over nozzle and turbine blades
D. steam expends over blades incompletely
Answer» C. steam expends partially over nozzle and turbine blades
107.

Which fuel has the lightest liquid petroleum fraction?

A. diesel
B. petrol
C. distillate
D. kerosene
Answer» C. distillate
108.

What does regenerative air preheater consists of?

A. rotor
B. skewers
C. propeller
D. piston
Answer» B. skewers
109.

Tubular air preheater of a boiler is also called as

A. recuperative air preheater
B. elliptical air preheater
C. ovoid air preheater
D. squarish air preheater
Answer» B. elliptical air preheater
110.

Gas flows through the nozzle from an area of            pressure (called the chamber) to one of            pressure

A. high, low
B. low, high
C. same, same
D. constant, infinite
Answer» B. low, high
111.

When a gas is pushed through a pipe, the gaseous molecules are                    by the pipe’s walls

A. attracted
B. absorbed
C. deflected
D. dissipated
Answer» D. dissipated
112.

A cubical block rests on an inclined plane of μ = 1/√3, determine the angle of inclination when the block just slides down the inclined plane?

A. 40°
B. 50°
C. 30°
D. 20°
Answer» D. 20°
113.

The coefficient of kinetic friction is less than the coefficient of static friction.

A. true
B. false
Answer» B. false
114.

Compressible flow is a flow that deals with

A. fluid temperature
B. fluid pressure
C. fluid density
D. fluid geometry
Answer» D. fluid geometry
115.

The exit velocity in the nozzle increases as per

A. stagnation point
B. continuity equation
C. prandtl number
D. newton’s law
Answer» C. prandtl number
116.

Critical pressure ratio is ratios of pressures at                    discharge.

A. minimum
B. none of the mentioned
C. optimum
D. maximum
Answer» E.
117.

A nozzle used to send fluid in coherent stream is called as

A. jet
B. high velocity nozzle
C. every nozzle sends fluid in coherent stream
D. none of the mentioned
Answer» B. high velocity nozzle
118.

In fountains the type of nozzle used is

A. none of the mentioned
B. turbulent jet
C. high speed nozzle
D. laminar jet
Answer» E.
119.

Cooling towers are rated in terms of

A. approach
B. range
C. both of the mentioned
D. none of the
Answer» D. none of the
120.

When humidity ratio of air ____ air is said to be dehumidified.

A. increases
B. decreases
C. remains constant
D. none of the mentioned
Answer» C. remains constant
121.

When unsaturated air flows over a sheet of water in an insulated chamber

A. specific humidity of air decreases
B. the water evaporates
C. both air and water are cooled during evaporation
D. all of the mentioned
Answer» B. the water evaporates
122.

The wet bulb temperature is the ____ temperature recorded by moistened bulb.

A. lowest
B. highest
C. atmospheric
D. none of the mentioned
Answer» B. highest
123.

The COP of absorption refrigeration system is

A. low
B. high
C. equal to that of vapour compression refrigeration system
D. none of the mentioned
Answer» B. high
124.

Water is used as a ____ in air conditioning units.

A. absorbent
B. refrigerant
C. absorbent and refrigerant
D. none of the mentioned
Answer» C. absorbent and refrigerant
125.

why is an analyser-rectifier combination is used in absorption refrigeration cycle?

A. to increase the amount of water vapour in ammonia vapour
B. to decrease the amount of water vapour in ammonia vapour
C. to eliminate the water vapour from ammonia vapour
D. all of the mentioned
Answer» D. all of the mentioned
126.

The vapour going to condenser is ____ in temperature and ____ in ammonia.

A. higher, less
B. higher, richer
C. lower, less
D. lower, richer
Answer» E.
127.

An increase in diameter means a _________ heat transfer coefficient.

A. larger
B. smaller
C. zero
D. infinite
Answer» C. zero
128.

If there is a decrease in viscosity, the heat transfer coefficient ____________

A. increase
B. decrease
C. remains same
D. becomes zero
Answer» B. decrease
129.

Double pipe water cooling condensers have a capacity at around ________

A. 10 tr
B. 20 tr
C. 30 tr
D. 50 tr
Answer» B. 20 tr
130.

In evaporative condensers, ___________ used to extract heat from the condensing refrigerant.

A. air is
B. both air and water are
C. water is
D. either air or water is
Answer» C. water is
131.

Shell and coil type condensers have a capacity at around ________

A. 10 tr
B. 20 tr
C. 30 tr
D. 50 tr
Answer» E.
132.

Which type of fins are the most commonly used fin type in condensers?

A. annular fin
B. plate type fins
C. tube fin
D. extended double pipe
Answer» C. tube fin
133.

What is the relation between heat rejection ratio (HRR) and Coefficient of performance (COP)?

A. hrr = 1 + 1/cop
B. hrr = 1+ cop
C. hrr = cop/2
D. hrr = 1/cop
Answer» B. hrr = 1+ cop
134.

Evaporative condensers are used in places where water is _________

A. scarce
B. plenty
C. moderately available
D. sufficient
Answer» B. plenty
135.

Evaporative condensers combine the features of a _____________ in a single unit.

A. cooling tower and water-cooled condenser
B. falling tower and water-cooled condenser
C. cooling tower and air condenser
D. rising film tower and water-cooled condenser
Answer» B. falling tower and water-cooled condenser
136.

In traditional Air conditioners in home appliances, what is the type of condenser used?

A. natural convection type
B. forced convection type
C. flash type
D. rotary condensers
Answer» C. flash type
137.

What is the meaning of heat rejection ratio (HRR) of a condenser?

A. ratio of heat rejected to the heat absorbed
B. ratio of heat absorbed to the heat rejected
C. ratio of heat required to the heat lost
D. ratio of heat wasted in a cycle to the heat absorbed
Answer» B. ratio of heat absorbed to the heat rejected
138.

In traditional Refrigerators in home appliances, what is the type of condenser used?

A. natural convection type
B. forced convection type
C. furnace type
D. rotary condensers
Answer» B. forced convection type
139.

Condensers and evaporators together form a ____________

A. heat exchanger
B. refrigeration system
C. thermocouple
D. heating system
Answer» C. thermocouple
140.

The process of extraction of the certain required amount of water from air is known as ___________

A. heating
B. cooling
C. humidification
D. dehumidification
Answer» E.
141.

The reciprocal of thermal conductivity is known as __________

A. thermal conductance
B. surface resistance
C. specific conductance
D. thermal resistivity
Answer» E.
142.

The total loss in a tertiary cycle is?

A. sum of losses in the individual cycles
B. product of losses in the individual cycles
C. sum of products of individual losses
D. none of the mentioned
Answer» C. sum of products of individual losses
143.

In case of mercury-steam-sulphur dioxide cycle, which is the bottoming fluid?

A. mercury
B. steam
C. sulphur dioxide
D. cannot say
Answer» D. cannot say
144.

Room air conditioners and packaged units are examples of _________

A. direct expansion systems
B. indirect expansion systems
C. chilled water systems
D. indirect contraction systems
Answer» B. indirect expansion systems
145.

In case of Sodium-mercury-steam cycle, which is the topping fluid?

A. mercury
B. steam
C. sodium
D. cannot say
Answer» D. cannot say
146.

Which of these can be used as a fluid in the bottoming fluid?

A. mercury
B. ammonia
C. calcium
D. sodium
Answer» C. calcium
147.

Which of these can also be used as a topping fluid?

A. sodium
B. calcium
C. boron
D. titanium
Answer» B. calcium
148.

The addition of sulphur dioxide in a tertiary cycle is at?

A. high temperature
B. low temperature
C. too high temperature
D. none of the mentioned
Answer» C. too high temperature
149.

In the mercury steam cycle, the steam cycle is called?

A. bottoming cycle
B. middle cycle
C. topping cycle
D. none of the mentioned
Answer» B. middle cycle
150.

Apart from mercury & steam, which of these is a component of tertiary cycle?

A. nitrogen di-oxide
B. water
C. carbon di-oxide
D. sulphur di-oxide
Answer» E.