Accuracy And Precision

Question

Four students repeatedly measure a fixed rod whose true length is 50.0 cm, and one student's readings cluster tightly around 48.0 cm every time. How is this student's measurement best described?

RankGuru · Accepted Answer

NCERT Class 11, Chapter 2 (Units and Measurements) draws a clear distinction between accuracy, which is closeness to the true value, and precision, which is the reproducibility of repeated readings. The student's readings cluster tightly together, indicating high reproducibility and therefore high precision. However, they centre on 48.0 cm rather than the true 50.0 cm, showing a consistent offset and therefore poor accuracy. This is the signature of a systematic error, such as a mis-zeroed instrument. The option accurate but not precise is wrong because the readings are not close to the true value. The option both accurate and precise is wrong as the persistent 2.0 cm deviation rules out accuracy. The option neither accurate nor precise is wrong since the tight clustering demonstrates clear precision. A sanity check confirms that a fixed offset with low scatter is exactly the textbook example of precise but inaccurate measurement.

Accuracy And Precision

Select the correct option:

🔒 Solution Hidden from View

More physics and measurement Practice Questions

Repeated measurements of a standard 50.0 gram mass cluster tightly between 46.9 gram and 47.1 gram a...

A workshop technician uses a screw gauge whose pitch is 1 mm and whose circular scale carries 100 eq...

An experiment determines acceleration due to gravity using a pendulum, with the period known to 1% a...

A researcher derives the time period of a simple pendulum and suspects it depends on length and grav...

An observatory uses the parallax method to measure the distance of a nearby star by recording its an...

A teacher writes the kinetic energy expression for a moving ball and asks students to confirm its di...

A physicist examines the coefficient of viscosity that appears when describing the slow flow of hone...

A student records the period of an oscillating spring four times as 2.01 s, 2.05 s, 1.99 s and 2.03 ...

A traffic study records a vehicle moving at a steady speed of 72 km/h along a straight highway segme...

A surveyor multiplies a measured length of 4.2 m by a measured width of 3.15 m to find the area of a...

A student tries to verify an equation containing a sum of a trigonometric term and a constant using ...

While studying photon energy, a learner encounters Planck's constant in the relation linking energy ...

About This Question

Solution