Do we know WHAT light is?
Light is a form of energy that travels in waves. It's made up of tiny particles called photons. Photons carry energy, which allows us to see things and enables many other processes on Earth.
We experience light everyday, every minute and every moment of our lives. Light is everywhere. We sense light but do we ever understand the physical meaning of light. Definitively, light is a form of radiation that is visible to the human eye. It is made up of tiny particles called photons, which travel in waves. Photons have no mass, but they do carry energy. Photons are tiny packets of energy that make up light. Packets of energy are called quanta and a quantum of light is a photon.
Light not only enables us to see but we depend on light for various other life sustaining processes such as photosynthesis, the process by which plants use sunlight to make food. Light also helps us to regulate our sleep-wake cycle.
How Light interacts with Matter?
Light interacts with matter in different ways and these phenomena explain the behaviour of many things around us.
i) Reflection: This is the simplest interaction light has with matter. When light hits a surface, it can bounce off. Reflection of light enables us to see. This is called reflection. Mirrors are a good example of reflection.
ii) Refraction: When light passes through a transparent material, it can bend. This is called refraction. A prism can refract light to create a rainbow.
iii) Absorption: When light hits an object, some of the photons are absorbed by the object, and some are reflected. The reflected photons travel to our eyes, and our brains interpret them as the color of the object.
* Colour: Light can be different colors, like red, orange, yellow, green, blue, indigo, and violet. The color of light is determined by its wavelength.
(+) How is light produced from Heat?
Light is a form of energy. As the fundamental law goes by, energy can neither be created nor destroyed. Similarly, light energy can be produced from heat energy. When heat is provided, electrons get excited. The excited electron steps out of its orbit. This extra energy is released in the form of photons. This obeys the law of conservation of energy as well as the law of conservation of mass.
