Recent Post

Online typing jobs without investment daily payment

There are a few online typing jobs that offer daily payment without investment. However, it is important to note that these jobs are often very competitive, and the pay is usually low. Examples of online typing jobs without investment in daily payment Data entry: Data entry jobs involve typing data into a computer system. This can include tasks such as entering customer information, transcribing documents, or updating databases. There are many websites that offer data entry jobs, such as Upwork, Fiverr, and Captioning: Captioning jobs involve typing the audio of videos and movies into text. This is a good option for people who are good at typing quickly and accurately. There are a number of websites that offer captioning jobs, such as and TranscribeMe. Transcription: Transcription jobs involve typing the audio of recorded conversations into text. This can include tasks such as transcribing medical interviews, legal proceedings, or business meetings. There are

Physical Optics

Physical Optics Notes for Class 11 - 12

Poynting vector

The amount of energy passing through unit area placed perpendicular to direction of a electromagnetic wave propagating is called poynting vector.

Wave front

At any moment, locus of particles on a wave which are in phase is called wave front.

Plane wave front

Locus of particles which are in phase or parallel rays coming from infinity is called plane wave front.


The small rectangular opening which has long length but a very small width is called slit.

Coherent source

Two light sources are said to be coherent if they emit waves having constant phase difference.

Interference fringe

When interference takes place on a plane or screen, some parallel bright and dark lines or pattern are found. This bright or dark patterns are called interference fringes.


The spreading of light rays passing through narrow opening or around corner is called diffraction of light.

Fresnel's class of diffraction

Light source at finite distance emits light rays and when they travel round the corner and creates a fringe pattern on screen placed at finite distance. This pattern is called fresnel's class of diffraction.

Fraunhofer class of diffraction

Light rays coming from infinity creates a pattern on screen at infinity. It is called Fraunhofer class of diffraction.

Diffraction grating

A plastic slide having large number of equidistant slits used for measuring wavelength of light is called diffraction grating.

Grating constant

If width of each slit of a grating is a and each opaque scratch has width of b, (a+b) is called grating constant.


The process by which vibration of light of wave can be confined in a definite plane is called polarization.


Popular Posts

Finance and Business Finance

Online typing jobs without investment daily payment

Earn money online without investment for students

Importance of Business Finance

What is finance in accounting?

The Importance of Information and Communication Technology

Search in Google by Shadow Power 24