Daily Current Affairs : 24-October-2023
Interactions between matter and radiation are diverse and intriguing, leading to the vibrant world we perceive. These interactions, which include Rayleigh scattering, Mie scattering, and fluorescence, shed light on the mesmerizing phenomena in the natural world.
Rayleigh Scattering: Painting the Sky Blue
- Air molecules scatter light, with shorter wavelengths being scattered more intensely.
- Blue light, having the shortest visible wavelength, scatters the most, rendering the sky its iconic blue hue.
- This phenomenon is known as Rayleigh scattering, explaining the vivid blue skies on sunny days.
Mie Scattering: Unraveling the Mystery of Clouds
- Clouds appear white due to Mie scattering, caused by light scattering through larger particles such as water droplets.
- Unlike Rayleigh scattering, Mie scattering involves larger particles, creating the diffused light that gives clouds their bright white appearance.
Fluorescence: Illuminating the Invisible
- Fluorescence is the emission of light by a substance that absorbed light or electromagnetic radiation.
- Objects absorb higher energy light (e.g., blue) and emit it at lower energy levels (e.g., red) through this luminescent process.
- Fluorescence occurs when electrons absorb photons, moving to higher energy levels before releasing energy and returning.
- If electron spin changes, the process becomes phosphorescence, distinct from fluorescence.
Applications of Fluorescence: Lighting Up Our World
- Fluorescence finds applications in diverse fields:
- Mineralogy: Identifying minerals based on fluorescence properties.
- Medicine: Various diagnostic tools and imaging techniques.
- Chemical Sensors: Fluorescence spectroscopy for precise chemical analysis.
- Biological Detection: Fluorescent labeling for biological research.
- Cosmic-Ray Detection: Utilized in scientific research and space exploration.
- Lighting Technology: Vacuum fluorescent displays, cathode-ray tubes, and fluorescent lamps.
- Gemology: Identifying gemstones based on their unique fluorescence patterns.
Fluorescence in Mammals: Nature’s Hidden Glow
- Fascinatingly, recent studies have revealed that the bodies of numerous mammal species fluoresce.
- All known mammalian orders exhibit some form of fluorescence, illuminating these creatures in unexpected ways.
- Notably, 107 mammal species possess fluorescent fur, showcasing the remarkable diversity of fluorescence in the animal kingdom.
Important Points:
- Rayleigh Scattering:
- Air molecules scatter light, with shorter wavelengths scattered more intensely.
- Blue light, having the shortest visible wavelength, scatters the most, creating the blue sky.
- Known as Rayleigh scattering, it explains the blue color of the sky on sunny days.
- Mie Scattering:
- Clouds appear white due to Mie scattering caused by light scattering through larger particles like water droplets.
- Mie scattering involves larger particles, creating diffused light and giving clouds their bright white appearance.
- Fluorescence:
- Fluorescence is the emission of light by a substance that absorbed light or electromagnetic radiation.
- Objects absorb higher energy light (e.g., blue) and emit it at lower energy levels (e.g., red) in this process.
- Fluorescence occurs when electrons absorb photons, move to higher energy levels, and then release energy as light.
- Phosphorescence, a related process, occurs when electron spin changes during this transition.
- Applications of Fluorescence:
- Mineralogy: Identifying minerals based on fluorescence properties.
- Medicine: Utilized in various diagnostic tools and imaging techniques.
- Chemical Sensors: Used in fluorescence spectroscopy for precise chemical analysis.
- Biological Detection: Fluorescent labeling aids biological research.
- Lighting Technology: Applied in vacuum fluorescent displays, cathode-ray tubes, and fluorescent lamps.
- Gemology: Identifying gemstones based on their unique fluorescence patterns.
- Fluorescence in Mammals:
- Recent studies reveal that bodies of many mammal species fluoresce.
- All known mammalian orders exhibit some form of fluorescence.
- 107 mammal species have fur that fluoresces, highlighting the diversity of fluorescence in the animal kingdom.
Why In News
Interactions between matter and radiation are diverse and intriguing, leading to the vibrant world we perceive. These interactions, which include Rayleigh scattering, Mie scattering, and fluorescence, shed light on the mesmerizing phenomena in the natural world, revealing the intricate dance between particles and light that defines the beauty of our universe.
MCQs about Fluorescence
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What causes the blue color of the sky on sunny days?
A. Absorption of blue light by air molecules
B. Reflection of blue light by clouds
C. Mie scattering by water droplets
D. Rayleigh scattering by air molecules
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Why do clouds appear white?
A. Absorption of all colors of light
B. Mie scattering by larger particles like water droplets
C. Reflection of sunlight
D. Absorption of blue light and scattering of other colors
-
What is fluorescence?
A. Emission of light by a substance that absorbs light
B. Reflection of light by a surface
C. Absorption of light by a substance
D. Scattering of light by particles in the atmosphere
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In which application is fluorescence NOT used?
A. Mineralogy
B. Medicine
C. Radioactive decay
D. Biological Detection
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