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⚛️ Physics  ·  Units and Measurements  ·  NEET & JEE

A vernier caliper has 20 vernier divisions coinciding with 19 mm on the main scale (main scale least count 1 mm). If the main scale reads 12 mm and the 6th vernier division coincides, the reading is:

Answer: 12.30 mm.

  • A 12.06 mm
  • B 12.30 mm
  • C 12.60 mm
  • D 12.15 mm

Correct answer: B. 12.30 mm

Explanation: Least count = 1 mm - (19/20) mm = 0.05 mm. Reading = 12 mm + 6 × 0.05 mm = 12.30 mm.

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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