← Junior Engineer
Past Questions
Pelton wheel is well suited for operating under
A)
Low heads
B)
High heads
C)
Normal heads
D)
None of these
Based on established principles in the relevant subject area, the correct and most appropriate choice is 'None of these' (Option D).
To avoid cavitation the turbine runners are made of cast steel and coated with
A)
Tungsten
B)
Cast iron
C)
Stainless steel
D)
Chromium
Based on established principles in the relevant subject area, the correct and most appropriate choice is 'Stainless steel' (Option C).
Requirement for refrigerants should be
A)
Non-poisonous
B)
Non- explosive
C)
Non-corrosive
D)
All of these
Based on established principles in Mechanical Engineering, the correct and most appropriate choice is 'All of these' (Option D).
The engine requires overhauling in case of
A)
Poor compression
B)
Excessive consumption of lubricating oil
C)
Mechanical failure
D)
All of these
Based on established principles in Mechanical Engineering, the correct and most appropriate choice is 'All of these' (Option D).
The flows of an unbounded fluid over a surface is called
A)
External flow
B)
Internal flow
C)
Open flow
D)
Normal flow
Based on established principles in Mechanical Engineering, the correct and most appropriate choice is 'External flow' (Option A).
Centrifugal pump has the advantage over reciprocating pump
A)
Smooth and evenflow
B)
Heavier in weight
C)
Low speed
D)
Torque not uniform
Based on established principles in Mechanical Engineering, the correct and most appropriate choice is 'Low speed' (Option C).
The temperature of saturation of air or the point beyond which any further cooling would result in condensation is called
A)
Absolute humidity
B)
Wet-bulb temperature
C)
Absolute temperature
D)
Dew point
The correct answer is **dew point**. Dew point is the temperature to which air must be cooled, at constant pressure and moisture content, for it to become saturated. Any further cooling below this temperature causes water vapor to condense into liquid water.
Why the others are incorrect:
- **Absolute temperature**: This is a temperature scale measured from absolute zero (e.g., Kelvin), not a humidity-related saturation point.
- **Wet-bulb temperature**: This is the temperature indicated by a wet thermometer bulb and relates to evaporative cooling; it is not the saturation/condensation threshold.
- **Absolute humidity**: This is the mass of water vapor per unit volume of air, not a temperature.
In air conditioning system the term used for air entering through doors, windows and other openings is termed as
A)
Condensation
B)
Infiltration
C)
Evaporation
D)
Conduction
Based on established principles in the relevant subject area, the correct and most appropriate choice is 'Condensation' (Option A).
“The intensity of pressure at any point in a fluid, at rest is the same in all direction”. It is
A)
Planck’s law
B)
Pascal’s law
C)
Chezy’s law
D)
Archimedes principal
Based on established principles in Mechanical Engineering, the correct and most appropriate choice is 'Planck’s law' (Option A).
Mechanical efficiency of the turbine is the ratio of
A)
Power developed by the runner / Power available at the turbine shaft
B)
Power available at the turbine shaft / Power developed by the runner
C)
Overall efficiency / Hydraulic efficiency
D)
Volumetric efficiency / Volumetric efficiency
Mechanical efficiency of a turbine is defined as the ratio of the power available at the turbine shaft to the power developed by the runner. It accounts for mechanical losses such as bearing and disc friction between the runner and the shaft output. Hence, option (b) is correct.
Why the others are incorrect:
- (a) Power developed by the runner / Power available at the turbine shaft is the inverse of mechanical efficiency.
- (c) Overall efficiency / Hydraulic efficiency is not the definition of mechanical efficiency; overall efficiency is the product of hydraulic, mechanical, and volumetric efficiencies (where applicable).
- (d) Volumetric efficiency / Volumetric efficiency equals 1 and is unrelated to mechanical efficiency.
Zeroth law of thermodynamics defines
A)
Internal energy
B)
External energy
C)
Temperature
D)
Pressure
Based on established principles in Mechanical Engineering, the correct and most appropriate choice is 'Internal energy' (Option A).
In a centrifugal pump the sum of the suction head and delivery head is called
A)
Gross Head
B)
Static Head
C)
Effective Head
D)
Manometric Head
Based on established principles in Mechanical Engineering, the correct and most appropriate choice is 'Static Head' (Option B).
The clutch is located between the transmission and the
A)
Engine
B)
Rear engine
C)
Propeller shaft
D)
Differential
Based on established principles in the relevant subject area, the correct and most appropriate choice is 'Propeller shaft' (Option C).
Position of the piston when it stops at the furthest point away from the cranksheft is
A)
BDC
B)
TDC
C)
CI
D)
SI
The piston is farthest from the crankshaft at the Top Dead Centre (TDC), which is the extreme upper position in the cylinder. Hence option **b (TDC)** is correct.
Why the others are incorrect: **BDC** (Bottom Dead Centre) is the piston’s farthest position *toward* the crankshaft, not away from it. **SI** and **CI** refer to engine types—Spark Ignition and Compression Ignition—not piston positions.
The type of fuel used in heavy commercial vehicle is
A)
Petrol
B)
Gas
C)
Battery
D)
Diesel
Heavy commercial vehicles such as trucks and buses typically use diesel because diesel engines provide higher torque, better fuel efficiency, and greater durability for heavy loads and long-distance operation. Petrol is more common in light vehicles, battery power is not the standard fuel for heavy commercial vehicles in conventional exams, and gas is used only in some specialized or alternative-fuel vehicles, not as the usual answer here.
An indication of ignition quality of a diesel engine is given by
A)
Detonation
B)
Octane number
C)
Pre-ignition
D)
Cetane number
Based on established principles in Mechanical Engineering, the correct and most appropriate choice is 'Detonation' (Option A).
Rotating mass with a large moment of inertia connect to the crankshaft of the engine is called
A)
Catalytic Converter
B)
Flywheel
C)
Exhaust manifold
D)
Fuel pump
Based on established principles in Mechanical Engineering, the correct and most appropriate choice is 'Exhaust manifold' (Option C).
The flow in a river during the period of heavy rainfall is
A)
Steady, uniform, two-dimensional
B)
Unsteady, uniform, three-dimensional
C)
Unsteady, non-uniform, three-dimensional
D)
Steady, non-uniform, three-dimensional
Based on established principles in Mechanical Engineering, the correct and most appropriate choice is 'Unsteady, non-uniform, three-dimensional' (Option C).
Whenever a material is loaded within elastic limit, stress is........................strain.
A)
equal to
B)
inversely proportional to
C)
directly proportional to
Based on established principles in Mechanical Engineering, the correct and most appropriate choice is 'equal to' (Option A).
Inspection is considered to be a tool of
A)
Quality control
B)
Material management
C)
Production control
D)
Plant layout
Based on established principles in Mechanical Engineering, the correct and most appropriate choice is 'Quality control' (Option A).
The design of thin cylinderical shells is based on
A)
longitudinal stress
B)
arithmetic mean of the hoop and the longitudinal stress
C)
geometric mean of the hoop and the longitudinal stress
D)
hoop stress
Based on established principles in Mechanical Engineering, the correct and most appropriate choice is 'geometric mean of the hoop and the longitudinal stress' (Option C).
CPM stands for
A)
Critical Process Method
B)
Combined Process Method
C)
Critical Path Method
D)
Common Planning Method
Based on established principles in Mechanical Engineering, the correct and most appropriate choice is 'Critical Path Method' (Option C).
A process of joining similar metal by application of heat with or without application of pressure & addition of filler material -
A)
welding
B)
balancing
C)
rivetting
D)
none of these
Based on established principles in Mechanical Engineering, the correct and most appropriate choice is 'balancing' (Option B).
The principal types of fit are
A)
Interference
B)
Transition
C)
Clearance
D)
All of these
Based on established principles in the relevant subject area, the correct and most appropriate choice is 'All of these' (Option D).
A mechanism consisting of four links is called ............................mechanism
A)
Compound
B)
Simple
Based on established principles in Mechanical Engineering, the correct and most appropriate choice is 'Compound' (Option A).