Question

What is a dimensionless quantity ?

Explain what is monochromatic light ?


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Answer 1

What is a dimensionless quantity ?

A quantity which does not have the basic physical units such as length, mass, temperature, etc. There are many quantities that do not have any physical unit but are used in measurements. Ex:- 1, i, π, googol,etc.

Explain what is monochromatic light ?

Light of one wavelength or colour is known as monochromatic light. Ex:- Red colour means only 1 colour or wavelength i.e only and does not include any other colours.

Extra information:-

Scalar quantity:-

Scalar quantities are quantities that have only magnitude. They do not have a direction. Ex:- Mass, Speed, Distance, etc.

Vector quantity:-

Vector quantities are quantities that have both magnitude and direction. Ex:- Displacement, Velocity, etc.

Polychromatic light:-

Light having many wavelengths or colours is known as polychromatic light. Ex:- White colour consists of all 7 colours i.e it is a mixture of all 7 colours.

What is light:-

Light refers to electromagnetic radiation (EC) whether it is visible or not. Under visible: visible light and under invisible: radio waves, infrared, UV,etc. Light has dual nature i.e both as particle and wave.

Answer 2

Answer:

1) What is a dimensionless quantity ?

$\longmapsto$ Dimensionless quantity is a quantity which is independent or doesn't have a physical or fundamentals unit like length, mass, time etc.

$\longmapsto$ Dimensionless quantity is a purely number.

$\longmapsto$ Dimensionless quantity is also known as quantity of dimensions.

2) Explain what is monochromatic light ?

$\longmapsto$ The light of different fundamental colours retain their colour intact - which shows that each colour of the spectrum is called monochromatic light.

$\longmapsto$ Example : Sodium lamp is a common source of monochromatic light.

Extra Information :-

$\leadsto$ Refraction Of Light :

• The chance in direction of the path of light while travelling from one transparent medium to another obliquely is called refraction of light.

$\leadsto$ Laws of Refraction :

1) The first law :

• The incident ray, the refracted ray and the normal at the point of incidence on the refracting surface all lie in the same plane.

2) The second law :

• The second law of refraction was discovered by Dutch Scientist Willebrod Snell, so this law of refraction is called Snell's Law.

$\leadsto$ Dispersion of Light :

• The phenomenon of splitting up of white light into its constituent colours on passing through a refraction medium is called dispersion of light.

$\leadsto$ Scattering of Light :

• When light wave passes through the atmosphere, it is absorbed by the molecules of air, these molecules further emit visible radiation in all directions and this phenomenon is called scattering of light.