Mechanic Quiz
Questions: 16 · 10 minutes
1. In a simple series lighting circuit, one bulb filament breaks and creates an open circuit. What happens to the other bulbs in that circuit?
They go out because the current path is interrupted
They become brighter because resistance falls
They stay at the same brightness through a parallel path
They flash until the battery voltage stabilizes
2. An engine takes unusually long to reach operating temperature, and the cabin heater remains weak in cool weather. Which fault is the best fit?
A thermostat stuck closed
A thermostat stuck open
A blocked radiator core
A cooling fan that runs too slowly
3. Blue exhaust smoke that continues after the engine has warmed up most strongly suggests what?
Coolant is circulating too quickly through the radiator
The fuel mixture is excessively rich
Engine oil is entering the combustion process
Normal condensation is leaving the exhaust system
4. A correctly rated fuse blows immediately each time it is replaced. What should a mechanic infer first?
The battery probably needs a higher-capacity fuse
The alternator belt is definitely slipping
The fuse rating should be increased until it holds
The circuit likely has excessive current draw, possibly from a short
5. What is the alternator's main role while a conventional combustion-engine vehicle is running?
To supply electrical power and recharge the battery
To meter fuel into the combustion chambers
To engage the flywheel and crank the engine
To convert transmission speed into wheel torque
6. During hard acceleration in a manual-transmission vehicle, engine speed rises rapidly but road speed does not increase proportionally. What is the most likely cause?
A thermostat opening too early
A slipping clutch
A wheel bearing adjusted too tightly
A locked differential
7. What is the primary purpose of engine oil in a running engine?
To raise the fuel's octane rating during combustion
To reduce friction and carry heat away from moving parts
To provide hydraulic pressure for the cooling system
To prevent electricity from reaching the spark plugs
8. A 12-volt source is connected across a 6-ohm resistance. Using Ohm's law, approximately how much current flows?
72 amperes
0.5 ampere
6 amperes
2 amperes
9. A compression test finds two adjacent cylinders significantly lower than the others. Which fault is a strong possibility?
A weak battery in the key fob
A partially restricted air filter
A head-gasket leak between the adjacent cylinders
Two clogged fuel injectors as the only possible cause
10. A driver feels a regular pulsation through the brake pedal during ordinary braking, without ABS activation. Which condition most commonly matches this symptom?
Low windshield-washer fluid
A worn brake-pad warning tab
Brake-rotor thickness variation or runout
Incorrect parking-brake cable adjustment
11. After an engine is fully warm, it produces persistent dense white exhaust with a sweet smell, and the coolant level keeps falling. What is the best explanation?
Coolant is entering one or more combustion chambers
Normal water vapor from a cold exhaust
Too much fuel is producing carbon-rich exhaust
Worn piston rings are allowing engine oil to burn
12. Why is a differential used in a vehicle's driven axle?
To make both wheels lock whenever the vehicle turns
To let the driven wheels rotate at different speeds while turning
To keep the inside wheel turning faster than the outside wheel
To disconnect the engine from the transmission during shifts
13. A tire shows excessive wear on both outer shoulders while the center has more tread. What is the most likely cause?
Chronic overinflation
Incorrect toe alignment alone
Chronic underinflation
A wheel that is slightly out of balance
14. A vehicle tracks straight while cruising but pulls sharply to one side only when the brakes are applied. What is the most likely area to inspect first?
Wheel balance at the rear axle
The differential gear ratio
Static wheel alignment as the sole cause
Unequal braking force at the front wheels
15. A scan tool reports the standardized OBD-II code P0302. What does this code indicate?
Low oxygen-sensor voltage on bank 2
A transmission fault in second gear
A random misfire with no identified cylinder
A detected misfire in cylinder 2
16. Which tool is specifically designed to tighten a fastener to a specified turning force?
A torque wrench
A compression gauge
A test light
A bearing puller