Electrical SI Units Quiz

11th Grade

Reviewed by Ekaterina Yukhnovich

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By Thames

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Quizzes Created: 10017 | Total Attempts: 9,652,179

| Attempts: 31 | Questions: 20 | Updated: Mar 13, 2026

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1. Ohm’s law is commonly written as V = IR.

True

False

Concept: ohm’s law relationship. Ohm’s law relates potential difference, current, and resistance. It’s widely used for basic circuit calculations and unit checks.

Explanation

Concept: ohm’s law relationship. Ohm’s law relates potential difference, current, and resistance. It’s widely used for basic circuit calculations and unit checks.

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About This Quiz

This quiz focuses on Electrical SI Units, testing knowledge of key concepts like power and resistance in electrical circuits. It evaluates the understanding of fundamental relationships such as the equation W = V \u00d7 A and the unit of resistance. This knowledge is crucial for anyone studying electrical engineering o... see moreworking in related fields, enhancing their grasp of essential electrical principles. see less

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2. Since 1 V = 1 J/C, higher voltage means more energy per unit charge.

True

False

Concept: voltage interpretation. Voltage tells you how much energy each coulomb of charge can gain or lose. This is why voltage is related to 'push' in circuits.

Explanation

Concept: voltage interpretation. Voltage tells you how much energy each coulomb of charge can gain or lose. This is why voltage is related to 'push' in circuits.

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3. Using SI units consistently helps prevent calculation errors in physics.

True

False

Concept: consistency reduces mistakes. Mixing units (like cm with m) can create hidden factor errors. SI consistency makes dimensional checks straightforward.

Explanation

Concept: consistency reduces mistakes. Mixing units (like cm with m) can create hidden factor errors. SI consistency makes dimensional checks straightforward.

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4. “Ω” is the symbol for ohm, and it should be capital omega.

True

False

Concept: correct symbol usage. Resistance uses the ohm symbol Ω (capital omega). Using the correct symbol avoids confusion with other letters.

Explanation

Concept: correct symbol usage. Resistance uses the ohm symbol Ω (capital omega). Using the correct symbol avoids confusion with other letters.

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5. 1 coulomb is equal to 1 ampere-second (A·s).

True

False

Concept: charge-current-time link. Current is charge per time, so charge equals current × time, that gives C = A·s.

Explanation

Concept: charge-current-time link. Current is charge per time, so charge equals current × time, that gives C = A·s.

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6. If V is volts and I is amperes, the unit of resistance R is:

A/V

V/A

V·A

W/S

Concept: resistance as ratio. From V = IR, resistance is R = V/I. That means Ω = V/A.

Explanation

Concept: resistance as ratio. From V = IR, resistance is R = V/I. That means Ω = V/A.

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7. If a device draws 2 A at 12 V, its power is:

6 W

10 W

24 W

144 W

Concept: power from V and I. Use P = VI, so P = 12 × 2 = 24 W. This is simple multiplication with correct unit reasoning.

Explanation

Concept: power from V and I. Use P = VI, so P = 12 × 2 = 24 W. This is simple multiplication with correct unit reasoning.

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8. The SI unit of resistance is the:

Coulomb (C)

Volt (V)

Ohm (Ω)

Ampere (A)

Concept: resistance unit. Electrical resistance is measured in ohms (Ω). It links voltage and current in simple circuits.

Explanation

Concept: resistance unit. Electrical resistance is measured in ohms (Ω). It links voltage and current in simple circuits.

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9. Which statement is correct?

Coulomb measures energy

Coulomb measures charge

Volt measures current

Ampere measures resistance

Concept: correct quantity–unit matching. Coulomb is charge, volt is potential difference, ampere is current, and ohm is resistance. Matching these correctly is essential for unit consistency.

Explanation

Concept: correct quantity–unit matching. Coulomb is charge, volt is potential difference, ampere is current, and ohm is resistance. Matching these correctly is essential for unit consistency.

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10. 1 volt is equal to:

C/J

J/C

W·s

A/S

Concept: volt definition. Voltage is energy per charge, so V = J/C.

Explanation

Concept: volt definition. Voltage is energy per charge, so V = J/C.

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11. The SI unit of electric potential difference is the:

Watt (W)

Volt (V)

Tesla (T)

Farad (F)

Concept: voltage unit. Voltage measures energy per unit charge. It is expressed in volts (V).

Explanation

Concept: voltage unit. Voltage measures energy per unit charge. It is expressed in volts (V).

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12. Which unit is best for electrical resistance?

Concept: resistance symbol recognition. Resistance is measured in ohms, symbol Ω. Volts measure potential difference, amperes measure current, and watts measure power.

Explanation

Concept: resistance symbol recognition. Resistance is measured in ohms, symbol Ω. Volts measure potential difference, amperes measure current, and watts measure power.

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13. A kilowatt-hour (kWh) is a unit of energy, not power.

True

False

Concept: energy vs power. kWh means power × time, which is energy. It’s commonly used on electricity bills.

Explanation

Concept: energy vs power. kWh means power × time, which is energy. It’s commonly used on electricity bills.

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14. Which is the best unit for measuring electrical energy used by a device over time?

Concept: energy unit. Energy is measured in joules (J) in SI. Practical billing often uses kWh, but in SI the energy unit is the joule.

Explanation

Concept: energy unit. Energy is measured in joules (J) in SI. Practical billing often uses kWh, but in SI the energy unit is the joule.

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15. The unit for electric current is:

Ampere (A)

Coulomb (C)

Volt (V)

Watt (W)

Concept: current unit. Current is a base SI quantity measured in amperes. It describes charge flow per unit time.

Explanation

Concept: current unit. Current is a base SI quantity measured in amperes. It describes charge flow per unit time.

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16. The SI unit of electric charge is the:

Ampere (A)

Coulomb (C)

Volt (V)

Ohm (Ω)

Concept: charge unit. Charge is measured in coulombs (C). It relates to current and time through how much charge flows.

Explanation

Concept: charge unit. Charge is measured in coulombs (C). It relates to current and time through how much charge flows.

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17. The SI unit of power can be written as W = V × _____.

Power (W) in an electrical context is defined as the rate at which electrical energy is transferred or converted. It can be calculated using the formula W = V × I, where V represents voltage (in volts) and I represents current (in amperes). This relationship shows that power is directly proportional to both voltage and current, meaning that increasing either will result in a higher power output. Thus, the blank in the equation should be filled with "I" to reflect this fundamental principle of electrical power.

Explanation

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18. Which derived unit can be expressed as kg·m²/s³?

Joule (J)

Watt (W)

Pascal (Pa)

Newton (N)

Concept: watt in base units. Watt is joule per second, and joule is kg·m²/s². Dividing by s gives kg·m²/s³.

Explanation

Concept: watt in base units. Watt is joule per second, and joule is kg·m²/s². Dividing by s gives kg·m²/s³.

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19. Resistance has units of ______ per ampere.

Resistance is defined as the opposition to the flow of electric current. According to Ohm's Law, resistance (R) is calculated as the voltage (V) across a component divided by the current (I) flowing through it, expressed as R = V/I. Therefore, the unit of resistance is volts per ampere, which is commonly referred to as ohms (Ω). This relationship highlights that for every ampere of current, a certain number of volts are required to overcome the resistance.

Explanation

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