WBBSE Notes For Class 6 Maths Arithmetic Chapter 7 Metric System

Arithmetic Chapter 7 Metric System

Arithmetic Chapter 7 Unit

Definition: How many times or a part of a body or a physical quantity is measured in comparison to that of a definite and convenient part of the body or a physical quantity taken as standard measurement then this definite and convenient part is called the unit.

Unit is of two types namely:

1. Fundamental unit and

2. Derived unit.


Fundamental Unit :

Definition:

1. The units of those physical quantities which do not depend on one another and from whose units, the units of all other quantities can be formed are called Fundamental Units.

2. For example, the unit of length, the unit of mass, the unit of time, etc. are the fundamental units.

Important Definitions Related to the Metric System

Derived Unit :

Definition:

1. The units formed from one or more fundamental units are called Derived Units.

2. For example, the unit of area, the unit of volume, etc. are the derived units.

 

Arithmetic Chapter 7 International Fundamental unit

At present, there are 7 internationally recognized fundamental units.

These are:

 

WBBSE Notes For Class 6 Maths Arithmetic Chapter 7 Metric System 1

WBBSE Class 6 Metric System Notes

Arithmetic Chapter 7 Metric system or Decimal system

Definition:

  1. The system of measurements in which the interrelation among the units can be determined by taking 10 as the base is called the metric system or decimal system.
  2. In other words, in this system, any unit in comparison to its preceding or succeeding unit is 10 times or parts.

The list of measurements in the metric system is given below:

1. Units in the measurement of length:

  1. 10 millimeters (mm) = 1 centimeter (cm)
  2. 10 centimeters = 1 decimeter (dcm)
  3. 10 decimeters = 1 meter (m)
  4. 10 meters = 1 decameter (Dm)
  5. 10 decameters = 1 hectometer (Hm)
  6. 10 hectometers = 1 kilometer (Km)

Understanding the Metric System

From the above list, we get the following relations:

1 kilometer

= 1 x 10 hectometers = 10 hectometers

=10 x 10 decameters = 100 decameters

= 100 x 10 meters = 1000 meters

= 1000 x 10 decimeters = 10000 decimeters

= 10000 x 10 centimeters = 100000 centimeeters

= 100000 x 10 millimeters = 1000000 millimeters

Again, 1 meter

= 1 x 10 decimeters = 10 diameters

= 10 x 10 centimeters = 100 centimters

= 100 x 10 millimeters = 1000 millimeters

Also 10 kilometers = 1 myriametre.

From the following, we can keep in mind these units easily

 

WBBSE Notes For Class 6 Maths Arithmetic Chapter 7 Metric System 2

Short Questions on Metric Units

2. Unit of the measurement of mass:

 

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From the above list, we can write,

 1 kilogram 

(1 x 10) hectograms =  10 hectograms

 (10 × 10) decagrams  = 100 decagrams

 (100 x 10) grams = 1000 grams

 (1000 x 10) decigrams = 10000 decigrams

 (10000 × 10) centigrams = 100000 centigrams

(100000 × 10) milligrams = 1000000 milligrams

Again,

10 kilograms = 1 myriagram

100 kilograms = 1 Quintal

10 Quintals = 1 metric ton

1 Metric ton = (10 x 100) kilograms

= 1000 kilograms

Examples of Real-Life Applications of the Metric System

3. Unit of measurement of volume

1. Unit of measurement of the volume of liquid

The unit of measurement of the volume of liquid matter is Litre.

10 millilitres = 1 centilitre

10 centilitres = 1 decilitre

10 decilitres = 1 litre

10 litres = 1 decalitre

10 decalitres = 1 hectolitre 

10 hectolitres = 1 kilolitre

So from the above list, we can write,

1 kilolitre 

(1 × 10) hectolitres = 10 hectolitres

(10x 10) decalitres = 100 decalitres 

(100 x 10) litres = 1000 litres

(1000 x 10) decilitres = 10000 decilitres 

(10000 × 10) centilitres = 100000 centilitres

= (100000 x 10 millilitres = 1000000 millilitres

Again,

1 Litre = 10 decilitre

= 100 centilitres

= 1000 millilitres

1 kilolitre = 1000 Litres

 

2.  Unit of measurement of the volume of solid body

The unit measurement of the volume of a solid body is cubic meters.

 

WBBSE Notes For Class 6 Maths Arithmetic Chapter 7 Metric System 4

Now, 

1 cubic metre = 1 metre x,1 metre x 1 metre

= 10 decimetres x 10 decimetres x 10 decimetres

= 1000 cubic decimetres

1 cubic metre = 1 metre x 1 metre x 1 metre

= 100 cm x 100 cm x 100 cm

= \(10^6\) cubic cm

1 cubic kilometre = 1 km x 1 km x 1 km

= 1000 m x 1000 m x 1000 m

= \(10^9\) cubic meters

= \(10^9 \times 10^6\) cubic centimeters

= \(10^15\) cubic cm

 

4. Unit of measurement of Area

The unit of measurement of the area of any surface is Are.

 

WBBSE Notes For Class 6 Maths Arithmetic Chapter 7 Metric System 5

 

∴ 1 sq. kilometre = 1 km x 1 km

= 1000 m x 1000 m

= \(10^6\) sq. meters

1 sq. meter 1m x 1m

= 100 cm x 100 cm

= 10000 sq. cm

= \(10^4\) sq. cm

1 Are = 1 sq decametre

= 100 sq. meters

1 hectare = 100 ares

= 100 x 100 sq. metres

= 10000 sq. metres

1 centesimal = 40.4678 sq. metres

= 1000 sq. links [ 1 link = 0-2011 metres, 100 links 1 chain]

1 Acre = 100 centesimal

= 4046.78 sq. metres 

= 60 katas

1 Katha = 1.66 centesimal

1 Bigha = 20 Kathas 

= 33.2 centesimals

 

5. Unit of measurement of Time

1 minute = 60 seconds

1 hour = 60 minutes

= 60 x 60 seconds

= 3600 seconds

1 day = 24 hours

1 week = 7 days

= (7 x 24) hours

= 168 hours

1 Paksha = 15 days

1 month = 30 days

1 year = 12 months

= 52 weeks

= 365 days

1 century = 100 years.

Leap-Year: If the number of any year is divisible by 4, then the year is called Leap-Year.

The number of days of a Leap Year = 365+ 1

= 366 days

and the number of days in the month of February in a leap-year = 28+ 1

= 29 days.

Real-Life Scenarios Involving Distance and Weight Measurements

Arithmetic Chapter 7 Unit Of Different Measurements

1. Unit of Length

Unit of Length:

The smallest unit of length is Farmy and the greatest unit is Parsec. 

1 Farmy (F) 10-15 metre  

1 Angstram (Å) = 10-10 metre 

1 micrometer or micron (um) = 10-6 meter 

1 nanometer (nm) = 10-9 metre 

1 light year = 9.46 x 1015 metres

[The distance traveled by light in 1 year in zero medium is called 1 light year.]

1 parsec = 3.08 x 1016 metres = 3.26 light years.


2. The unit of force is Newton 

3. The unit of work or energy is Joule 

4. The unit of power is Watt

5. The unit of electric charge is Coulomb

6. The unit of electrical potential-Difference is Volt

7. The unit of electrical resistance is the Ohm 

8. The unit of pressure is Paskel

9. The unit of the Plane cone is Radian

10. The unit of frequency is Hertz.

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