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⚛️ Physics  ·  Units and Measurements  ·  NEET & JEE

The density of a cube is found by measuring its mass and the length of one side. If the mass has a relative error of 2% and the side length has a relative error of 1%, the relative error in the calculated density is:

Answer: 5%.

  • A 5%
  • B 3%
  • C 2%
  • D 1%

Correct answer: A. 5%

Explanation: Density = mass/(side)³, so the relative error adds as 2% + 3×1% = 5%, since the error in a cubed quantity is tripled.

The 7 SI Base UnitsLengthmetre (m)fundamentalMasskilogram (kg)Timesecond (s)Electric Currentampere (A)Temperaturekelvin (K)Amount ofSubstancemole (mol)LuminousIntensitycandela (cd)Every other physical quantity is derived by combining powers of these 7 base units

The 7 SI base units. All derived units (newton, joule, watt, volt, etc.) can be expressed as combinations of these 7 fundamental units raised to various powers.

Concept context

SI base units, dimensional analysis, significant figures, and error propagation. The toolkit every physics calculation relies on.

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