IGCSE Physics Physical Quantities

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LEARNING OBJECTIVES:

By the end of this section, you will be able to:

  • Understand the meaning of the term "physical quantity"
  • Give examples of  physical quantities
  • State the correct units of recoring gthe physical quantities
  • Convert between different units of physical  quantities

 So, What is meant by the words " Physical Quantity?"

  • Well, A physical quantity is a physical property of a material or  a system.
  • It is a  physical property   that can be expressed by measurement.
  • A physical quantity can be expressed as a value, which is the algebraic multiplication of a numerical value and a unit.

Examples of physical quantities:

  • mass,  length, density, velocity, force and  length

Units for measuring physical quantities:

When we take measurements of physical quantities , we need to record them  in terms of units,These units  are standardized values.Below we shall learn about various unist for expressing measurments of physical quantities.

Physical quantity: Length

  • Length is a physical quantity that can be expressed in terms of units such as the millimetre, centineter, decimeter, kilometer , hectometre,etc.
  • Following is the relation between various units of length:
  • (a) 1kilometer=1000millimetres
  • (b) 1metre=10 decimetres
  • (c) 1metre=100 centimetres
  • (d) 1 metre=1000 millimetres
  • (e) 1 metre= 0.1 decametres
  • (f) 1 metre = 0.01 hectometres
  • (g) 1 metre= 0.001 kilometres

Physical quantity: Mass

  • Mass is a physical quantity that can be expressed in terms of units such as the milligram, centigram decigram, kilogram , hectogram,etc.
  • Following is the relation between various units of length:
  • (a) 1kilogram=1000milligram
  • (b) 1gram=10 decigrams
  • (c) 1gram=100 centigram
  • (d) 1 gram=1000 milligrams
  • (e) 1 gram= 0.1 decagram
  • (f) 1 gram = 0.01 hectograms
  • (g) 1 gram= 0.001 kilograms

Physical quantity: Capacity

  • Mass is a physical quantity that can be expressed in terms of units such as the millilitre, centilitre, decilitre, kilolitre , hectolitre,etc.
  • Following is the relation between various units of capacity:
  • (a) 1kilogram=1000milligram
  • (b) 1litre=10 decilitre
  • (c) 1litre=100 centilitre
  • (d) 1 litre=1000 millilitre
  • (e) 1 litre= 0.1 decalitre
  • (e) 1 litre = 0.01 hectolitre
  • (f) 1 litre= 0.001 kilolitres

Physical quantity: Time

  • Time is a physical quantity that can be expressed in terms of units such as the hours, minutes, seconds, days etc
  • Following is the relation between various units of time:
  • (a)1 year =365 days
  • (b) 1 day =24 hours
  • (c) 1 hour = 60 minutes
  • (d) 1 minute= 60 seconds
  • (e) 1 second= 1000 milliseconds
  • (f) 1 day =86 400 seconds
  • (h) 1 hour =3 600 000 milliseconds

 

 

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