Trade-based questions for diploma-engineering candidates in mechanical, electrical, electronics and automobile engineering - Question Bank

1. What is the primary function of a resistor in an electronic circuit?
A) To store charge
B) To oppose the flow of current
C) To induce a magnetic field
D) To amplify voltage
2. In automotive terms, what does 'engine displacement' refer to?
A) The total volume swept by all pistons in one engine cycle
B) The volume of fuel injected per cycle
C) The volume of exhaust gases produced
D) The volume of the cooling system
3. What is the main purpose of the rotor in an AC induction motor?
A) To generate voltage
B) To create a rotating magnetic field
C) To convert electrical energy into mechanical energy
D) To provide magnetic flux
4. Which type of circuit breaker uses a bimetallic strip to trip the circuit?
A) Magnetic circuit breaker
B) Thermal circuit breaker
C) Hydraulic circuit breaker
D) Electronic circuit breaker
5. What is the function of a transformer's core?
A) To provide electrical insulation
B) To conduct the magnetic flux between the windings
C) To dissipate heat generated in the windings
D) To increase the voltage rating
6. Which law governs the relationship between the flow rate of a fluid and the pressure difference across a pipe?
A) Newton's Law of Viscosity
B) Bernoulli's Principle
C) Hagen-Poiseuille Equation
D) Archimedes' Principle
7. What is the term for the measure of how much a material resists scratching or abrasion?
A) Toughness
B) Hardness
C) Ductility
D) Brittleness
8. Which component in a car's suspension system absorbs shocks and provides a smoother ride?
A) Spring
B) Shock absorber (damper)
C) Control arm
D) Ball joint
9. What is the purpose of the clutch in a manual transmission vehicle?
A) To provide engine braking
B) To allow the engine to be disconnected from the transmission temporarily
C) To change gear ratios
D) To lubricate the transmission gears
10. Which of the following is a common method for hardening steel?
A) Annealing
B) Normalizing
C) Quenching and tempering
D) Stress relieving
11. What is the phenomenon where a changing magnetic field induces an electromotive force (EMF) in a conductor?
A) Ohm's Law
B) Joule Heating
C) Electromagnetic Induction
D) Capacitance
12. Which type of AC generator produces voltage and frequency that are directly proportional to its speed?
A) Induction generator
B) Permanent magnet alternator
C) Synchronous generator
D) DC generator
13. What is the primary role of an amplifier in an electronic circuit?
A) To reduce signal amplitude
B) To increase signal amplitude
C) To filter out unwanted frequencies
D) To rectify AC signals
14. In a semiconductor, doping is done to:
A) Increase its melting point
B) Increase its electrical conductivity
C) Decrease its physical strength
D) Make it non-conductive
15. What is the unit of electrical power?
A) Volt
B) Ampere
C) Ohm
D) Watt
16. Which type of gear is used to transmit motion between two non-parallel shafts?
A) Spur gear
B) Helical gear
C) Bevel gear
D) Worm gear
17. What is the function of the radiator in an automobile's cooling system?
A) To heat the engine oil
B) To transfer heat from the coolant to the surrounding air
C) To store excess coolant
D) To regulate the coolant flow rate
18. Which manufacturing process involves forcing molten metal into a mold cavity?
A) Forging
B) Extrusion
C) Casting
D) Rolling
19. What is the term for the maximum stress a material can withstand before it begins to deform permanently?
A) Ultimate tensile strength
B) Yield strength
C) Elastic limit
D) Fatigue strength
20. What is the primary advantage of using a three-phase AC power system over a single-phase system?
A) Simpler wiring
B) More efficient power transmission and generation of rotating magnetic fields
C) Lower voltage requirements
D) Easier voltage regulation
21. Which electronic component acts as a switch and amplifier?
A) Resistor
B) Capacitor
C) Inductor
D) Transistor
22. What does Ohm's Law describe the relationship between?
A) Voltage, current, and resistance
B) Power, voltage, and current
C) Charge, voltage, and capacitance
D) Frequency, inductance, and capacitance
23. What is the function of the alternator in a car?
A) To start the engine
B) To charge the battery and power electrical systems while the engine is running
C) To control the engine's speed
D) To provide braking force
24. Which automotive system is responsible for delivering fuel to the engine's cylinders?
A) Ignition system
B) Exhaust system
C) Fuel system
D) Cooling system
25. In metallurgy, what is annealing primarily used for?
A) To increase hardness
B) To reduce brittleness and improve ductility
C) To create a protective surface layer
D) To increase tensile strength
26. What is the purpose of a governor in a prime mover?
A) To control fuel supply
B) To regulate speed under varying loads
C) To manage lubrication
D) To monitor exhaust temperature
27. Which type of motor is commonly used in applications requiring variable speed control?
A) DC series motor
B) DC shunt motor
C) Synchronous motor
D) Variable frequency drive (VFD) controlled induction motor
28. What is the function of a rectifier in an electrical system?
A) To convert AC to DC
B) To convert DC to AC
C) To increase voltage
D) To reduce current
29. Which law states that for every action, there is an equal and opposite reaction?
A) Newton's First Law
B) Newton's Second Law
C) Newton's Third Law
D) Archimedes' Principle
30. What does the term 'viscosity' measure?
A) The density of a fluid
B) The resistance of a fluid to flow
C) The surface tension of a fluid
D) The compressibility of a fluid
31. Which type of engine typically uses spark plugs for ignition?
A) Diesel engine
B) Gasoline (Petrol) engine
C) Steam engine
D) Jet engine
32. What is the purpose of a catalytic converter in an automobile?
A) To improve engine cooling
B) To reduce harmful emissions
C) To increase fuel injection efficiency
D) To enhance ignition timing
33. Which component of a car's braking system converts hydraulic pressure into mechanical force?
A) Brake pedal
B) Brake fluid
C) Brake caliper/wheel cylinder
D) Brake lines
34. What is the primary function of the crankshaft in an internal combustion engine?
A) To control valve timing
B) To convert reciprocating motion of pistons into rotational motion
C) To ignite the fuel-air mixture
D) To supply fuel to the cylinders
35. Which type of heat treatment is used to increase the hardness and strength of steel by heating and rapid cooling?
A) Normalizing
B) Hardening
C) Tempering
D) Annealing
36. What is the term for the process of removing impurities from a metal by heating it below its melting point?
A) Smelting
B) Refining
C) Annealing
D) Tempering
37. In a three-phase induction motor, what is the purpose of the stator winding?
A) To provide mechanical support
B) To generate a rotating magnetic field
C) To connect the motor to the power supply
D) To dissipate heat
38. What is the main component of a typical transistor?
A) One semiconductor layer
B) Two semiconductor layers
C) Three semiconductor layers
D) Four semiconductor layers
39. Which of the following is a measure of the opposition to current flow in an AC circuit?
A) Resistance
B) Inductance
C) Capacitance
D) Impedance
40. What is the function of a capacitor in an AC circuit?
A) To oppose changes in voltage
B) To oppose changes in current
C) To store energy in an electric field
D) To convert AC to DC
41. In electronics, what does a diode primarily do?
A) Amplifies signals
B) Stores electrical energy
C) Allows current to flow in only one direction
D) Generates AC voltage
42. What is the primary purpose of a flywheel in an engine?
A) To increase power output
B) To smooth out rotational speed fluctuations
C) To cool the engine
D) To improve fuel efficiency
43. Which type of welding uses a non-consumable tungsten electrode?
A) SMAW (Shielded Metal Arc Welding)
B) GMAW (Gas Metal Arc Welding)
C) GTAW (Gas Tungsten Arc Welding)
D) FCAW (Flux-Cored Arc Welding)
44. What does the term 'Pascal's Law' relate to?
A) Pressure in fluids
B) Heat transfer
C) Electrical resistance
D) Mechanical stress
45. Which type of bearing is best suited for high radial loads and moderate axial loads?
A) Ball bearing
B) Roller bearing
C) Thrust bearing
D) Plain bearing
46. What is the purpose of a commutator in a DC motor?
A) To increase torque
B) To reverse the direction of current in the armature winding
C) To regulate speed
D) To reduce sparking
47. Which of the following is a characteristic of a series DC generator?
A) Constant voltage output
B) Voltage increases with load
C) Voltage decreases with load
D) Constant current output
48. What is the unit of kinematic viscosity?
A) Pascal-second
B) Stokes
C) Newton per square meter
D) Joule per second
49. Which type of coupling is used to connect two shafts that are not perfectly aligned?
A) Flange coupling
B) Muff coupling
C) Universal coupling
D) Rigid coupling
50. In a DC motor, the back EMF is proportional to:
A) Applied voltage
B) Motor speed
C) Load torque
D) Armature resistance
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