Master Derived SI Units with Our Knowledge Assessment

1. A pascal is a 'small' unit, so pressures are often written in kPa.

True

False

Concept: Practical scale and prefixes. Many everyday pressures are thousands of pascals. Using kPa keeps numbers manageable and readable.

Explanation

Concept: Practical scale and prefixes. Many everyday pressures are thousands of pascals. Using kPa keeps numbers manageable and readable.

2. Which is the correct SI unit for density?

G/L

Kg/m³

N/m²

J/s

Concept: Density units. Density is mass per volume. In SI base units that becomes kg per cubic metre.

Explanation

Concept: Density units. Density is mass per volume. In SI base units that becomes kg per cubic metre.

3. Torque has the same base units as energy, but it represents a different physical quantity.

True

False

Concept: Same units, different meaning. Torque and energy can both be expressed as N·m. The context (rotation vs work) tells you which quantity is meant.

Explanation

Concept: Same units, different meaning. Torque and energy can both be expressed as N·m. The context (rotation vs work) tells you which quantity is meant.

4. Breaking derived units into base units helps check if an equation is dimensionally consistent.

True

False

Concept: Dimensional checking. Expressing everything in base units lets you see whether both sides match. This is a powerful way to catch mistakes.

Explanation

Concept: Dimensional checking. Expressing everything in base units lets you see whether both sides match. This is a powerful way to catch mistakes.

5. The SI unit of force is the:

Joule (J)

Newton (N)

Watt (W)

Pascal (Pa)

Concept: Force unit. Force is measured in newtons (N). It relates to mass and acceleration, so it’s a derived unit.

Explanation

Concept: Force unit. Force is measured in newtons (N). It relates to mass and acceleration, so it’s a derived unit.

6. The SI unit of energy is the joule (J).

True

False

Concept: Energy unit. Joule is the SI derived unit for energy and work. It connects force and distance.

Explanation

Concept: Energy unit. Joule is the SI derived unit for energy and work. It connects force and distance.

7. Pressure is measured in pascals (Pa).

True

False

Concept: Pressure unit. Pressure is force per area. The pascal is the SI unit derived from newtons and square metres.

Explanation

Concept: Pressure unit. Pressure is force per area. The pascal is the SI unit derived from newtons and square metres.

8. Which unit best matches 'force per unit area'?

Watt (W)

Pascal (Pa)

Joule (J)

Hertz (Hz)

Concept: Pressure definition. Pressure is force divided by area. Pascals are newtons per square metre.

Explanation

Concept: Pressure definition. Pressure is force divided by area. Pascals are newtons per square metre.

9. Which derived unit is named after a person and therefore has a capital symbol?

Metre (m)

Second (s)

Newton (N)

Mole (mol)

Concept: Naming convention and symbols. Units named after people use capital symbols (N, J, W, Pa). Base units like metre use lowercase symbols.

Explanation

Concept: Naming convention and symbols. Units named after people use capital symbols (N, J, W, Pa). Base units like metre use lowercase symbols.

10. Which derived unit matches 'energy per unit time'?

Newton (N)

Joule (J)

Watt (W)

Pascal (Pa)

Concept: Identifying power. Energy per time is power, measured in watts. This is a core mechanics derived unit.

Explanation

Concept: Identifying power. Energy per time is power, measured in watts. This is a core mechanics derived unit.

11. The SI unit of frequency is the hertz (Hz), which equals s⁻____.

Concept: Hertz as inverse seconds. Frequency counts cycles per second. So Hz = 1/s = s⁻¹.

Explanation

Concept: Hertz as inverse seconds. Frequency counts cycles per second. So Hz = 1/s = s⁻¹.

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12. If power is measured in W, then energy can be found from power × time in:

Pascals

Newtons

Joules

Coulombs

Concept: Power–energy link. Energy = power × time. Since W = J/s, multiplying by seconds gives joules.

Explanation

Concept: Power–energy link. Energy = power × time. Since W = J/s, multiplying by seconds gives joules.

13. 1 newton (N) is equal to:

Kg·m²/s²

Kg·m/s²

M/s²

Kg/s

Concept: Newton in base units. A newton is the force needed to accelerate 1 kg at 1 m/s². That makes N = kg·m/s².

Explanation

Concept: Newton in base units. A newton is the force needed to accelerate 1 kg at 1 m/s². That makes N = kg·m/s².

14. 1 joule (J) is equal to:

N/m

N·m

Kg·m/s

Pa·s

Concept: Joule meaning. Work/energy is force times distance, so J = N·m. This also expands to base units as kg·m²/s².

Explanation

Concept: Joule meaning. Work/energy is force times distance, so J = N·m. This also expands to base units as kg·m²/s².

15. The SI unit of power is the:

Joule (J)

Pascal (Pa)

Watt (W)

Volt (V)

Concept: Power unit. Power is the rate of energy transfer. The watt measures joules per second.

Explanation

Concept: Power unit. Power is the rate of energy transfer. The watt measures joules per second.

16. 1 watt (W) equals:

J·s

J/s

N·m²

Kg·m/s

Concept: Watt definition. Power is energy per time. So 1 W = 1 J/s.

Explanation

Concept: Watt definition. Power is energy per time. So 1 W = 1 J/s.

17. 1 pascal (Pa) equals:

N·m

N/m

N/m²

Kg·m/s

Concept: Pascal meaning. Pressure is force divided by area. So Pa = N/m².

Explanation

Concept: Pascal meaning. Pressure is force divided by area. So Pa = N/m².

18. The unit for momentum in SI is:

N·m

Kg·m²/s²

Kg·m/s

N/m²

Concept: Momentum units. Momentum is mass times velocity. That gives kg·m/s in SI.

Explanation

Concept: Momentum units. Momentum is mass times velocity. That gives kg·m/s in SI.

19. The unit 'kg·m²/s²' is equivalent to:

Newton (N)

Joule (J)

Pascal (Pa)

Watt (W)

Concept: Base-unit recognition. Joule expands to kg·m²/s². Newton is kg·m/s², and watt is kg·m²/s³.

Explanation

Concept: Base-unit recognition. Joule expands to kg·m²/s². Newton is kg·m/s², and watt is kg·m²/s³.

20. The SI unit of work/energy is the ______.

Concept: Energy unit recall. Work and energy share the same SI unit. That unit is the joule (J).

Explanation

Concept: Energy unit recall. Work and energy share the same SI unit. That unit is the joule (J).

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Derived SI Units Quiz: Test Your Knowledge Of Combined Units

1. A pascal is a 'small' unit, so pressures are often written in kPa.

2.

What first name or nickname would you like us to use?

2. Which is the correct SI unit for density?

3. Torque has the same base units as energy, but it represents a different physical quantity.

4. Breaking derived units into base units helps check if an equation is dimensionally consistent.

5. The SI unit of force is the:

6. The SI unit of energy is the joule (J).

7. Pressure is measured in pascals (Pa).

8. Which unit best matches 'force per unit area'?

9. Which derived unit is named after a person and therefore has a capital symbol?

10. Which derived unit matches 'energy per unit time'?

11. The SI unit of frequency is the hertz (Hz), which equals s⁻____.

12. If power is measured in W, then energy can be found from power × time in:

13. 1 newton (N) is equal to:

14. 1 joule (J) is equal to:

15. The SI unit of power is the:

16. 1 watt (W) equals:

17. 1 pascal (Pa) equals:

18. The unit for momentum in SI is:

19. The unit 'kg·m²/s²' is equivalent to:

20. The SI unit of work/energy is the ______.