Nature of Light: Wave and Particle

Introduction:

Photosynthesis is the process by which phototrophs convert light energy into chemical energy, which is then used to fuel the activities of cells in their environment. It is possible to store chemical energy in the form of sugars, which can be produced by combining water and carbon dioxide.

According to the definition of photosynthesis, the process occurs exclusively in the chloroplasts and is mediated by photosynthetic pigments such as chlorophyll a, chlorophyll b, carotene, and xanthophyll. Photosynthesis is used by all green plants and a few other autotrophic organisms to synthesise nutrients by converting carbon dioxide, water, and sunlight into organic compounds. Oxygen is produced as a by-product of the photosynthesis process. Let’s take a closer look at the photosynthesis process, reaction, and significance in greater detail.

Apart from green plants, photosynthesis applies to a wide range of other organisms. Several prokaryotes, such as cyanobacteria, purple bacteria, and green sulphur bacteria, are among those found in this group. Photosynthesis is present in these organisms, just as it is in green plants. Photosynthesis generates glucose, which is then utilised by the cell to power various functions. Oxygen is produced as a by-product of this physio-chemical reaction.

Factors Affecting Photosynthesis

The photosynthesis process requires several factors such as:

Light Intensity: The rate of photosynthesis increases as the amount of light available increases. The rate of photosynthesis, on the other hand, is reduced when the amount of light available is low.

The concentration of CO2: An increase in carbon dioxide concentration has been shown to accelerate the rate of photosynthesis. Carbon dioxide concentrations in the range of 300 – 400 parts per million (PPM) are usually sufficient for photosynthesis.

Temperature: It is necessary to maintain a temperature range between 25° and 35° C for photosynthesis to be carried out efficiently.

Water: Because water is an essential component of photosynthesis, a lack of it can result in problems with the uptake of carbon dioxide. When water is scarce, stomatal openings close, preventing the plant from retaining the amount of water it has stored inside.

Pollution: On the surface of the leaf, industrial pollutants and other particulates may accumulate. This can cause the pores of the stomata to become clogged, making it difficult for the plant to absorb carbon dioxide.

Nature of light

Lighting serves as an energy source for the human eye and brain, according to biological principles. The combination of the brain, the eye, and light is responsible for providing sight. When it comes to physics, two theories can be used to define light: the first defines light as particles, and the second theory defines light as waves.

It is the second theory that is most appropriate for explaining light when considering measurement equipment such as spectro[radio]meters, which measure light in wavelengths, and when considering other factors. As a result, the scope of this article is limited to wave theory.

The True Nature of Light

Lighting serves as an energy source for the human eye and brain from a biological perspective. Sight is provided by a combination of the brain, the eye, and light. When it comes to physics, two theories can be used to define light: the first defines light as particles, while the second defines light as waves.

It is the second theory that is most appropriate for explaining light when considering measurement equipment such as spectro[radio]meters, which measure light in wavelengths. Consequently, we will be concentrating on wave theory in this article.

The range of wavelengths just below 380 nm is referred to as ultraviolet [UV], and the range of wavelengths just above 780 nm is referred to as infrared [IR]. Even though these wavelength ranges are invisible to the human eye, they are still considered to be light by the scientific community.

A light source, such as a lamp, can only be seen when looking directly at it, or when looking at illuminated objects that reflect light from a source, such as a window. In a completely dark room with a light source on one side and an object on the other, as shown in the image below, this might be the case.

Whenever the eye is focused on the light source, it can see the light coming directly from it. There is visible light emanating from the source [A]. It is also possible to see light from the light source reflecting off the object [B] and reaching the eye. The object becomes visible as a result of the reflected light. In contrast, when looking straight ahead [C], even though light rays pass by, there is no visible light: one would be staring at a black wall.

Natural sources of light

The light that is produced naturally and without the involvement of humans is referred to as a natural source of light. Natural sources of light can be obtained from either an inanimate object or a living species in the environment.

Sun, stars, lightning, jellyfish, fireflies, glowworms, bush fires, angler fish, and other natural light sources animals are examples of natural light sources.

Dual nature of light

Because of the dual nature of light, it has been observed in some experiments to behave as a wave. The behaviour of light as a particle has been observed in other experiments.

In 1801, Thomas Young created a slit between two adjacent slits that allowed light to pass through. Constructive interferences resulted in the formation of light and dark bands, which alternated in a pattern of light and dark bands; the light bands are the result of constructive interferences, and the dark bands result from destructive interferences. If the light had been made up of small particles, the alternating light and dark bands would not have appeared on the screen.

Wave nature of light:

According to Newton, light is a stream of particles known as corpuscles of light, which are small clusters of light. Rutherford’s model could not account for the phenomena of interference and deflection, but it could account for reflection and refraction, which were both previously unaccounted for.

When Huygen proposed that light travels in the form of waves, later James Maxwell proposed that fight and other radiations are transmitted in the form of waves, and that these waves are associated with oscillating electric and magnetic fields.

Conclusion:

It is necessary to understand the properties of waves and electromagnetic radiation to comprehend the electronic structure of atoms. Energy is transmitted through space using periodic oscillations, which are known as waves. All waves are periodic, with recurrences occurring regularly in both space and time. Waves are distinguished by several interconnected characteristics, including wavelength (the distance between successive waves), frequency (the number of waves that pass a fixed point per unit time), speed (the rate at which the wave propagates through space), and amplitude, which is the magnitude of the oscillation about the mean position. The speed of a wave is equal to the product of the wavelength and the frequency of the wave is propagated. 

Electromagnetic radiation is made up of two perpendicular waves, one electric and one magnetic, which propagate at the speed of light and are therefore called electromagnetic radiation (c). EM radiation is a type of radiant energy that includes radio waves, microwaves, visible light, x-rays, and gamma rays. The frequencies and wavelengths of electromagnetic radiation vary depending on the source.