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Nature has bestowed the sense of sight to detect electromagnetic waves in a limited range of the electromagnetic spectrum. Light refers to electromagnetic radiation in this spectrum region (wavelengths ranging from 400 nm to 750 nm). We know and interpret the world around us primarily through light and our sense of vision.
From common experience, there are two factors we can intuitively say about light. The first is that it travels at breakneck speed, and the second is that it needs to travel in a single direction.
What is Reflection of Light?
It took some time for people to realise that the speed of light is measurable and finite. In a vacuum, it is currently accepted to be c = 2.99792458 x 108 m/s. However, for many purposes, c = 3 x 108 m/s is sufficient. This is because the speed of light in a vacuum is the highest speed that nature can achieve.
The insightful concept that light journeys in a straight line contradict what we learned: light is an electromagnetic wave of visible wavelength.
How can the two facts be reconciled?
The answer is that the wavelength of light is extremely small in comparison to the size of ordinary objects that we encounter daily (generally of the order of a few cm or larger).
In this case, the incident light can be thought to travel from one juncture to another along a straight line that connects them.
The path is referred to as a ray of light, and a grouping of such rays is referred to as a beam of light.
Using a ray picture of light, we examine the occurrences of reflection, refraction, and dispersion of light in this chapter. We will investigate image formation by plane and spherical trying to reflect and refract surfaces using the fundamental laws of refraction and reflection. The construction and operation of some virtual optical devices, including the human eye, are then described.
Light
Light is a type of energy that can be detected by the eyes.
There are three light sources: thermal sources, luminescent sources, and incandescent sources.
Photometry is a branch of light energy measurement.
Light Characteristics
Light waves were indeed electromagnetic waves with a transverse nature. The speed of light in a vacuum is 3 x 108 m/s, but it varies depending on the medium.
When light travels from one medium to another, its speed and wavelength change, but its frequency remains constant.
Important Phrases
(i) Luminous objects emit their light, such as the Sun, other stars, an oil lamp, and so on.
ii) Non-Luminescent Objects non-luminous objects are those that do not emit their light but become visible due to the reflection of light falling on them, such as the moon, table, chair, trees, and so on.
(iii) A ray of light is a straight line drawn in the direction of light propagation.
(iv) A beam of light grouping adjacent light rays.
(v) Illustration If a light ray from an object meets or appears to meet at a point after reflection or refraction, this point is known as the image of the object.
(vi) A real image is formed by the actual meeting of light rays. A real image can be obtained on a screen. The real image has been turned upside down.
(vii) A virtual image is created when light rays do not collide but appear to collide.
(viii) Light reflection refers to the rebounding of light rays into the same medium after striking a highly polished surface, such as a mirror.
Reflection Laws
There are two reflection laws.
(i) At the point of incidence, the incident ray, the reflected ray, and the normal are all in the same plane.
(ii) The incidence angle (i) is always equal to the reflection angle (r).
Mirror
A mirror is a reflective surface that is smooth and highly polished.
A plane mirror is a mirror with a highly polished plane surface. The various properties of the image formed by a plane mirror are,
Image size equals object size.
Image distance = object distance
A plane mirror can create only virtual image.
A man’s full image can be seen in a mirror half his height.
The number of images of an object placed between two plane mirrors when held at an angle is below.
Conclusion
Even though most microscope and lens manufacturers now create their proprietary coating formulations, magnesium fluoride is one of many materials used for thin-layer optical antireflection coatings. The overall effect of these antireflection measures is a dramatic improvement in image quality in optical devices due to increased transmission of visible wavelengths, reduced glare from unwanted reflections, and elimination of interference from wavelengths outside the visible light spectral range.
The reflection of visible light is a property of light behaviour required for all modern microscopes to function. One or more plane (or flat) mirrors within the microscope frequently reflect light, directing the light path through lenses that form the virtual images we see through the oculars (eyepieces). In microscopes, beamsplitters allow some light to be reflected while transmitting a portion of the morning to different parts of the optical system. Other optical components in the microscope, such as specially designed prisms, filters, and lens coatings, also contribute to image formation and rely heavily on the phenomenon of light reflection.
