NABTEB Auto Mechanic
Past Questions
20+ verified Auto Mechanic past questions for NABTEB. Step-by-step worked answers in 5 Nigerian languages.
Auto Mechanic topics (2)
Sample Auto Mechanic past questions
1. Engine oil mainly serves to:
- A. Add power
- B. Lubricate moving parts
- C. Cool tyres
- D. Charge battery
Answer: B
2. Battery in a car stores:
- A. Petrol
- B. Electrical energy
- C. Air
- D. Water
Answer: B
3. The device that ignites fuel in a petrol engine is the:
- A. Fuse
- B. Spark plug
- C. Radiator
- D. Alternator
Answer: B
4. Brake fluid is part of the:
- A. Cooling system
- B. Braking system
- C. Fuel system
- D. Exhaust
Answer: B
5. The four-stroke cycle includes intake, compression, power and:
- A. Reverse
- B. Exhaust
- C. Idle
- D. Brake
Answer: B
6. The component that stores electrical energy in a car is the:
- A. Radiator
- B. Battery
- C. Carburettor
- D. Muffler
Answer: B
AI Explanation
## The reasoning The **battery** is specifically designed to store electrical energy chemically and release it as electricity when needed. In a car, it powers the starter motor, lights, radio, and all electrical systems — especially when the engine is off. This is a straightforward application of **energy storage principles**: batteries convert chemical energy into electrical energy and vice versa. Think of it this way: when you charge your phone, the battery *stores* that energy for later use. A car battery does the same thing, just on a larger scale. ## Why the wrong options tempt you **Radiator (A)** — sounds technical and is important in cars, but it *cools* the engine using liquid, not electricity. **Carburettor (C)** — mixes air and fuel for combustion in older engines. It handles fuel, not electrical energy. **Muffler (D)** — reduces exhaust noise. It's about sound, not energy storage. These parts are all crucial, but they deal with *thermal, mechanical, or chemical processes* — not electrical storage. ## Quick takeaway **Only the battery stores electrical energy; the other parts manage heat, fuel, or sound.** Remember: "Battery = electrical storage" — it's in the name!
7. Engine overheating may be caused by low:
- A. Fuel
- B. Coolant
- C. Air
- D. Light
Answer: B
8. An engine that runs on petrol uses ___ ignition:
- A. compression
- B. spark
- C. magnetic
- D. manual
Answer: B
AI Explanation
Petrol engines use spark plugs to ignite the fuel-air mixture. Diesel engines use compression.
9. The function of the battery in a vehicle is to:
- A. cool the engine
- B. supply electrical power
- C. store fuel
- D. filter oil
Answer: B
AI Explanation
Battery stores electrical energy to start engine and power electrical systems.
10. Engine oil is changed primarily to:
- A. increase speed
- B. reduce friction and remove contaminants
- C. save fuel only
- D. improve sound
Answer: B
AI Explanation
Oil lubricates moving parts and carries away contaminants; degraded oil loses these properties.
11. The vehicle component that converts engine rotation to wheel movement is the:
- A. alternator
- B. transmission/gearbox
- C. battery
- D. radiator
Answer: B
AI Explanation
Transmission/gearbox transmits engine power to the wheels via various gear ratios.
12. An alternator:
- A. stores fuel
- B. generates electricity while engine runs
- C. stops the engine
- D. cleans the air
Answer: B
AI Explanation
Alternator charges battery and powers electrical systems while engine runs.
13. Brake fluid pressure is created by pressing the:
- A. throttle
- B. brake pedal
- C. clutch
- D. steering wheel
Answer: B
AI Explanation
Pressing the brake pedal pushes the master cylinder piston, sending fluid pressure to brakes.
14. Spark plugs ignite fuel in:
- A. petrol engines
- B. diesel engines
- C. electric motors
- D. hybrid only
Answer: A
AI Explanation
Spark plugs create the spark in petrol engines. Diesel ignites by compression heat.
15. Tyre tread depth affects:
- A. fuel economy only
- B. wet-road grip and braking distance
- C. engine noise only
- D. engine oil
Answer: B
AI Explanation
Worn tread reduces grip on wet roads, increasing braking distance and aquaplaning risk.
16. Coolant in the radiator:
- A. increases speed
- B. absorbs engine heat and dissipates it
- C. fuels the engine
- D. lubricates pistons
Answer: B
AI Explanation
Coolant circulates through the engine and radiator to manage temperature.
17. The clutch is used in vehicles with:
- A. automatic transmission
- B. manual transmission
- C. neither
- D. electric motor
Answer: B
AI Explanation
Manual transmission requires the clutch to disengage engine from gearbox during gear changes.
18. An air filter:
- A. increases engine speed
- B. removes dust from air entering the engine
- C. cleans engine oil
- D. discharges battery
Answer: B
AI Explanation
Clean air filter ensures only filtered air reaches combustion — protects engine wear.
19. An overheating engine may be caused by:
- A. fresh oil
- B. low coolant or faulty thermostat
- C. new spark plugs
- D. new tyres
Answer: B
AI Explanation
Common causes: low coolant, faulty thermostat, broken water pump or blocked radiator.
20. A 'jack' is used to:
- A. start the engine
- B. lift a vehicle off the ground
- C. fuel the engine
- D. stop the engine
Answer: B
AI Explanation
Vehicle jacks lift the car for tyre changes or under-vehicle work.
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