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⚛️ Physics  ·  Units and Measurements  ·  NEET & JEE

The order of magnitude of the mass of an electron (about 9.1 × 10⁻³¹ kg) is best expressed as:

Answer: 10⁻³⁰ kg.

  • A 10⁻³¹ kg
  • B 10⁻³⁰ kg
  • C 10⁻²⁹ kg
  • D 10⁻²⁸ kg

Correct answer: B. 10⁻³⁰ kg

Explanation: Since 9.1 rounds up past the midpoint, the order of magnitude is taken as the next power of ten, giving 10⁻³⁰ kg.

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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