Question

Read the tab for fundamental and supplementary units in SI system

Answer 1

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The international system of units (St system of units) The international system of units (abbreviated as SI, from the French system international (d' unites) is the modern form of the metric system and is the most widely used system of measurement. 

The SI is based on the following seven fundamental units and two supplementary units as listed in the table. 

Fundamental quantities and their units 

Name of a physical quantity

Symbol of quantity

SI unit Symbol of unit

Length L

Meter M

Mass M

Kilogram Kg

Time T or T

Second S

Temperature T or θ

Kelvin K

Current I

Ampere A

The above seven basic and two supplementary units are found to be sufficient to obtain the units of physical quantities from all branches of physics. 

• (ii) In addition to the fundamental units and the supplementary units, there are a large number of derived units on this system. Some of the derived units are listed in table.

Supplementary Units: Definitions 

1. Radian: One radian is the angle subtended at the centre of a circle by an arc equal in length to the radius of the circle. 

Plane angl

2. Steradian: One steradian is the solid angle subtended at the centre of a sphere, by that surface which is equal in area to the square of the radius of the sphere. 

If dA=r2 then dω=1steradian in case of complete surface area, the cubic angle subtended by it

Ω=r24πr2=4π steradian.

Answer 2

Answer:

The international system of units (St system of units) The international system of units (abbreviated as SI, from the French system international (d' unites) is the modern form of the metric system and is the most widely used system of measurement.

The SI is based on the following seven fundamental units and two supplementary units as listed in the table.

Fundamental quantities and their units

Name of a physical quantity

Symbol of quantity

SI unit Symbol of unit

Length L

Meter M

Mass M

Kilogram Kg

Time T or T

Second S

Temperature T or θ

Kelvin K

Current I

Ampere A

The above seven basic and two supplementary units are found to be sufficient to obtain the units of physical quantities from all branches of physics.

(ii) In addition to the fundamental units and the supplementary units, there are a large number of derived units on this system. Some of the derived units are listed in table.

Supplementary Units: Definitions

1. Radian: One radian is the angle subtended at the centre of a circle by an arc equal in length to the radius of the circle.

Plane angl

2. Steradian: One steradian is the solid angle subtended at the centre of a sphere, by that surface which is equal in area to the square of the radius of the sphere.

If dA=r2 then dω=1steradian in case of complete surface area, the cubic angle subtended by it

Ω=r24πr2=4π steradian.