Why an extended source is used in place of point source in the thin film?

Why an extended source is used in place of point source in the thin film?

In the case of interference in thin film , the narrow source limits the visibility of film. Hence only limited portion of the film is visible. If an extended source of light is used, then S1 A and S2A after reflection and internal reflection will reach the eye from a large portion of film.

Why do we use extended source of light?

Extended sources are meant to model spherical light sources. Unlike point sources, extended sources actually possess a radius, and as such are capable or producing shadows with fuzzy edges (penumbrae). If you do not specifically desire penumbrae in your image, use a point source instead.

Why is broad source necessary for Newton’s ring experiment?

Due to this reason to observe interference phenomenon in thin films, a broad source of light is required. With a broad source of light, rays of light are incident at different angles and the reflected parallel beams reach the eye or the microscope objective.

What kind of source is used in Newton’s ring experiment?

To study the formation of Newton’s rings in the air-film in between a plano-convex lens and a glass plate using nearly monochromatic light from a sodium-source and hence to determine the radius of curvature of the plano-convex lens.

What is difference between point source and extended source?

Point sources and extended sources of light….Solution.

Point Source of Light	Extended Source of light
eg: A pinhole through which sunlight is entering is a point source of light	eg: Sun is an extended source of light

When a point source of light is kept near a plane mirror?

only the reflected rays making a small angle with the mirror will meet at a point when produced backward.

What is the difference between point source and extended source?

What is a point source light?

1 : a source of radiation (such as light) that is concentrated at a point and considered as having no spatial extension. 2 : an identifiable confined source (such as a smokestack or wastewater treatment plant) from which a pollutant is discharged or emitted.

Why do the rings gets closer and finer as we move away from the center?

Rings get closer as the order increases (m increases) since the diameter does not increase in the same proportion. In transmitted light the ring system is exactly complementary to the reflected ring system so that the centre spot is bright.

What does a point source produce?

A point source is an area or physical place or thing from which something is produced or released. In physics it can be defined as a source of energy including sound or light energy.

Why do we need an extended source for Newton’s rings?

So for the whole ring to be formed we need a number of parallel rays from different points of the source. That is why we need an extended source to form the Newton’s rings. When I was a student we called the source an extended source, instead of a broad source.

What kind of lens is used in Newton rings experiment?

In a Newton rings experiment, a parallel beam from an extended source of light falls on a glass plate at an angle of incidence of 45°, making the reflected ray fall on a convex lens ( mostly a plano convex lens) put on a smooth flat glass plate normally with curved surface of the lens in contact with the flat glass plate.

How did the Newton’s Ring experiment get its name?

Newton’s Ring experiment is a phenomenon in which the reflection of light between two surfaces is used to create an interference pattern. It is named after the Scientist, Sir Isaac Newton.

Where is the interference path in Newton’s Ring experiment?

The Newton’s rings experiment shows interference rings between a flat surface and a spherical surface sitting on top of it. The interference path is the gap in between the sphere and the plane. The center is where the curve of the sphere is touching the plane.