9702 · 1.2
SI units flashcards
Revision flashcards for Cambridge 9702 SI units (syllabus 1.2). Flip, recall, then mark a real past-paper question.
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What are the two essential components of a physical quantity?
A numerical value (magnitude) and an associated unit.
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List three of the SI base quantities and their corresponding units.
Mass (kilogram, kg), Length (metre, m), Time (second, s).
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Explain what a derived unit is and provide an example.
A derived unit is formed by combining SI base units. For example, the Newton (N) for force is equivalent to kg m s⁻².
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What is the multiplier for the SI prefix 'nano' (n)?
10⁻⁹.
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What is the conversion factor for 1 electronvolt (eV) to Joules (J)?
1 eV = 1.6 × 10⁻¹⁹ J.
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What is the SI base unit for electric current?
Ampere (A).
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What does it mean for an equation to be 'dimensionally homogeneous'?
The units on both sides of the equation must be consistent (the same) when expressed in terms of base units.
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Convert 1 kilowatt-hour (kWh) to Joules (J).
1 kWh = 3.6 × 10⁶ J.
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What is the SI prefix and multiplier for 10⁹?
Giga (G).
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If speed is measured in m/s, what would be the derived unit for acceleration?
m/s² (or m s⁻²).
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What are the seven SI base quantities?
Length, mass, time, electric current, thermodynamic temperature, amount of substance, and luminous intensity.
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What is the derived SI unit for Pressure (Pascal, Pa) in terms of base units?
kg m⁻¹ s⁻²
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What is the primary purpose of using dimensional analysis on an equation?
To check for homogeneity, ensuring that the units on both sides of the equation are consistent and the equation is physically plausible.
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What is the SI base unit for thermodynamic temperature?
Kelvin (K).
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Express the derived unit for Power, the watt (W), in terms of SI base units.
kg m² s⁻³