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1.4 UNDERSTANDING MEASUREMENTS. INTRODUCTION TO PHYSICS. Determination of the actual value for particular physical quantity. MEASUREMENT. C onsistency. Ability of a measuring instrument to give readings with very small deviation or no deviation from the mean value.
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1.4 UNDERSTANDING MEASUREMENTS INTRODUCTION TO PHYSICS
Determination of the actual value for particular physical quantity. MEASUREMENT
Consistency • Ability of a measuring instrument to give readings with very small deviation or no deviation from the mean value. • Consistency of a measuring instrument can be improved by: • Taking a reading with caution • Eliminating parallax errors • Using the instrument which is not defective
Example • Mean value group A = 13.97s • Mean value group B = 14.30s
Accuracy • Ability of a measuring instrument to give readings nearest or almost equal to the actual value • Accuracy of a measurement can be improved by; • Repeating the measurement • Avoiding zero errors • Avoiding parallax errors • Using the measuring instrument with a higher sensitivity
Ability of a measuring instrument to detect a very small changes in the quantity being measured. Sensitivity
2 main types of errors • Systematic errors • Random errors Type of experimental errors
Systematic error : Zero error Is the error in an instrument that does not show zero reading when it should show zero reading (when not measuring any quantities)
VernierCalliper • Measure length with an accuracy of up to +0.1mm (0.01cm)
To measure the thickness or diameter of small objects. Micrometer Screw Gauge