Zero Error and Zero Correction
Zero error is the instrument's indicated value when the true input is zero; zero correction is the negative of zero error, and corrected reading equals observed reading plus zero correction.
Why this shows up in the exam
Caliper calibration · Micrometer correction · Balance tare adjustment
Learn the idea
A nonzero instrument indication at true zero is a signed bias that must be removed from every raw reading. If an empty scale already says plus two, that plus two belongs to the instrument, not the object, so subtract it from the observation.
🧠 Memory hook: Error is what the instrument adds; correction removes it.
Get this one clearly and it pays off every single time it shows up in the paper. 🎯
Formulas & facts to keep ready
- zero correction = - zero error — correction has opposite sign
- corrected = observed - zero error — equivalent correction formula
How to approach it
- 1Determine the signed zero indication
- 2Reverse its sign to get correction
- 3Apply the same correction to the raw observation
Common slip-ups that cost marks
- •Adding a positive zero error
- •Ignoring wraparound on a circular scale
- •Correcting the least count instead of the reading
🌟 That's the whole idea — you've got this. Try the practice set below; every question you attempt makes it stick a little harder.
Original chapter practice
Original questions for this chapter, not past-paper questions or an exact mapping to this individual concept.
A quantity Q is defined as Q = force^1 / speed^2. Which dimensional formula represents Q?
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