Accuracy refers to how close a measured value is to the true or accepted value. A measurement is said to be accurate if it is very near to the actual value.
Example: If the true length of a rod is 10 cm and the measured value is 9.9 cm, the measurement is accurate.
Precision refers to how close repeated measurements are to each other, regardless of whether they are close to the true value or not.
Example: If repeated measurements give values like 8.1 cm, 8.1 cm, and 8.1 cm, they are precise but may not be accurate.
Error is the difference between the measured value and the true value. Errors are unavoidable and occur due to limitations of measuring instruments or human observation.
Q1. Accuracy refers to: A) Closeness to true value B) Closeness among readings C) Instrument quality D) Zero error Answer: A Q2. Precision means: A) Correct value B) True value C) Repeated values close to each other D) No error Answer: C Q3. A measurement can be: A) Accurate but not precise B) Precise but not accurate C) Both accurate and precise D) All of the above Answer: D Q4. Which error occurs due to faulty instruments? A) Random error B) Gross error C) Systematic error D) Human error Answer: C Q5. Which method helps reduce random errors? A) Changing instrument B) Taking mean of readings C) Ignoring errors D) Using old instruments Answer: B
