Electrical & Diagnostic Basics Practice

1. Which unit measures voltage?

A. VoltB. AmpereC. OhmD. Watt-hour

2. Which unit measures current?

A. VoltB. OhmC. MillimeterD. Ampere

3. Which unit measures resistance?

A. AmpereB. LiterC. OhmD. Volt

4. Which unit measures electrical power?

A. MillimeterB. WattC. OhmD. Ampere-hour

5. What is Ohm's law for a simple resistor?

A. V = I × RB. V = I + RC. V = R − ID. V = I ÷ R

6. A 6-ohm resistor has 12 volts across it. What current flows?

A. 72 AB. 0.5 AC. 18 AD. 2 A

7. A load draws 3 A at 12 V. What is its electrical power?

A. 15 WB. 9 WC. 36 WD. 4 W

8. What is an open circuit?

A. A complete path with no interruptionB. A broken electrical pathC. An unrestricted fuel lineD. A correctly charged battery

9. What is a short circuit?

A. An unintended low-resistance pathB. A cable cut to its ideal lengthC. A fully isolated circuitD. A normal switch-off condition

10. What does a correctly rated fuse primarily protect against?

A. Every voltage fluctuationB. All corrosionC. Every mechanical vibrationD. Overcurrent

11. What should replace a blown fuse after diagnosing the fault?

A. A metal stripB. A wire wrapped around itC. The specified fuse type and ratingD. A higher rating to prevent blowing

12. How is voltage normally measured across a component?

A. With the circuit's fuse removed permanentlyB. With the meter connected in parallelC. By replacing the component with the meter's current inputD. Only by measuring its physical length

13. What should happen before a resistance measurement?

A. Safely remove power and address stored energyB. Increase circuit voltageC. Switch the meter to its current jackD. Bridge the fuse

14. What does a continuity test generally check?

A. Whether a device can carry full operating loadB. Whether a battery has its original capacityC. Whether a wire has the correct colorD. Whether a conductive path exists

15. Why test voltage drop under load?

A. It replaces the wiring diagramB. It increases battery voltageC. A weak connection may appear acceptable without current flowD. It removes every wiring fault

16. What is a relay?

A. A tire-pressure sensor onlyB. An electrically controlled switchC. An air filterD. A brake-fluid reservoir

17. What does DC mean?

A. Direct currentB. Double compressionC. Digital clearanceD. Drive control

18. What does AC mean?

A. Axle compressionB. Automatic continuityC. Air capacityD. Alternating current

19. What should you do with a damaged test lead?

A. Hold the exposed conductorB. Ignore damage on low settingsC. Stop using it and replace it appropriatelyD. Wrap bare wire around the probe

20. What is the best first step when unfamiliar with an EV high-voltage system?

A. Probe orange cables experimentallyB. Seek qualified training and follow manufacturer safety proceduresC. Assume disconnecting the 12-volt battery makes it safeD. Use ordinary gloves as insulation

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