Measurements

Objectives

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The Students Will be - Able to understand the need for measurement in our life. - Able to defi ne length, mass, time and volume. - Able to evaluate the values of some physical quantities in terms of their units and sub units. - Able to identify zero error and parallax error. - Able to measure the volume of solids and liquids. - Able to construct their own measuring tools (models)

Summary

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- The comparison of an unknown quantity with some known quantity is known as measurement. - All physical quantities have standard units for the sake of uniformity. - Length, mass and time are some of the fundamental physical quantities. - The SI units for Length - metre Mass - kilogram Time - second Volume - litre (or) cm3 - While using ruler, the accurate measurement can be arrived by avoiding three types of possible errors. - Volume of solids, liquids and regular objects is measured by direct measurement. - Volume of irregular objects can bemeasured by water displacement method. - Electronic balance is an instrument to provide accurate measurement of mass correct up to milligram