Measurement || Physical Quantity || Length || Time || Mass
Measurement is the comparison of unknown quantity
with known fixed standard quantity of the same kind.
Local System of Measurement:
A kind of measurement system which is used from the
ancient time and is unscientific and unreliable is known as local system of
measurement.
Disadvantages of Local System of
Measurement:
- They are unreliable.
- These units vary from person to person and place to place.
Standard Units of Measurement:
The scientists have developed different system of
measurement to maintain the uniformity in measurement.
Unit
The standard quantity of measurement which is
accepted throughout the world is called a unit. For example, meter (m),
kilogram (kg), second (s), etc.
Physical Quantity:
The quantities which can be measured are called
physical quantity. For example, Length,
Mass, Time, Temperature, Area, Volume, Pressure, etc.
Here are the some physical quantities with their SI
units:
|
Physical
Qauntity |
Standard
Units (SI Unit) |
|
|
|
Names |
Symbols |
|
Length |
Metre |
m |
|
Mass |
Kilogram |
kg |
|
Time |
Second |
s
|
|
Temperature |
Kelvin
|
k |
|
Electric
Current |
Ampere |
A |
System of Measurement:
MKS system : The
system of measurement in which length is measured in metre, mass in
kilogram and time in second is known as MKS system. This system is also
called metric system.
CGS system
: The system of measurement in which length is measured in centimetre, mass
in gram and time in second is known as MKS system. This system is also
called French system.
FPS system :
The system of measurement in which length is measured in foot, mass
in pound and time in second is known as MKS system. This system is also
called Bristish system.
Length: The
distance between any two points is known as length. Its SI unit is metre.
The following are the
multiples and sub-multiples of a metre:
1000
meter = 1 kilometer (km)
1
meter = 100 centimetre (cm)
1
centimetre = 10 millimetre (mm)
1000 millimetre = 1
metre (m)
Mass: The
quantity of matter contained in a body is called its mass. Its SI unit is
kilogram.
The following are the
multiples and sub-multiples of mass:
1000
milligram = 1 gram
1000
gram = 1 kilogram
100
kilogram = 1 quintal
10
quintal = 1 metric ton
Time
The interval between
any two events is called time. Its SI unit is second (s).
The following are the
multiples and sub-multiples of time:
60
seconds = 1 minutes
60
minutes = 1 hour
24
hours = 1 day
7
days = 1 week
365
days = 1 year
10
years = 1 decade