Every measurement contains some uncertainty because:

  1. SI units are not exact
  2. instruments have a limited resolution and readings involve judgement
  3. scientists make careless mistakes
  4. the true value always changes
Answer

B) instruments have a limited resolution and readings involve judgement

Even a perfect method is limited by the smallest scale division and by random effects. SLO P-11-A-07 · Understanding

Physics MCQ · More Physical Quantities and Measurement MCQs · Practise