# The Physical Quantityt

## The Physical Quantityt

• Submitted By: teyy2
• Date Submitted: 02/15/2009 1:26 AM
• Category: Science
• Words: 369
• Page: 2
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{text:bookmark-start} {text:bookmark-end} Base Quantities and Derived Quantities -Physical Quantity
A physical quantity is a quantity that can be measured. -Base Quantity
Base quantities are the quantities that cannot be defined in terms of other quantities. -Derived Quantity
Derived quantities are physics quantities derived from the base quantities through multiplication, division or both. {text:bookmark-start} {text:bookmark-end} Standard Form and Prefixes Standard form/Scientific Notation
Standard form or scientific notation is a convenient way to write very big or very small numerical values in a form of multiple of 10. Prefixes
Prefixes are names or symbols that precede a unit of measure to represent very big or very small numerical values in S.I. units. {text:bookmark-start} {text:bookmark-end} Scalar Quantities and Vector Quantities Define scalar quantity
Scalar quantities are physical quantities that have magnitude only. Define vector quantity
Vector quantities are physical quantities that have magnitude and direction. {text:bookmark-start} {text:bookmark-end} Measurements {draw:frame} Consistency
Consistency is the ability of an instrument in measuring a quantity in a consistent manner with only a small relative deviation between readings. Relative Deviation
The relative deviation is the percentage of mean deviation for a set of measurements and it is defined by the following formula: Accuracy
The accuracy of a measurement is how close the measurement made is to the actual value of the quantity of physics. Sensitivity
Sensitivity of a measuring tool is its ability to detect small changes in the quantity that is being measured. Systematic Error
Systematic errors are errors which tend to shift all measurements in a systematic way so their mean value is displaced. Zero Error
A zero error arises when the measuring instrument does not start from exactly zero. Random Error
Random errors arise from unknown and...