Refraction by lens A transparent medium surrounded by two curved surfaces, one or both of whose surfaces are spherical, is called a lens. There are two types of lenses- 1. convex 2. concave Convex lens The two spherical surfaces protruding outward in a lens are called convex lenses. Convex lens thicker in the middle … Read more
Reflection of light When a traveling ray of light hits a reflective surface, it returns back to the same medium or gets reflected, then this phenomenon is called reflection of light. Law of reflection There are two laws of the reflection of light, 1. An angle of incidence is equal to angle of reflection. … Read more
What is light Light is a medium with the help of which we are able to see any objects. In the absence of light, we cannot see any object because when light falls on an object, it gets reflected and reaches our eyes, then we feel the presence of that object. Reflection of light … Read more
Accuracy, Precision And Error Analysis Accuracy All those observations taken by an instrument which are close to the actual value of a physical quantity are called actual values. That is, the accuracy of a measurement is the value that tells us how close the measured value of a quantity is to … Read more
The Universe The immense sky that surrounds the Earth and all the celestial bodies present in it (eg- Milky way, stars, planets, satellites, etc.) and the entire energy is called the universe as a whole. The study related to the universe is called Cosmology. The universe is so huge, which we cannot even imagine. … Read more
The milky way The milky way is a huge body of billions of stars. The stars remain bound to the galaxies, for this the gravitational force is responsible among the four fundamental forces: gravitational force, electromagnetic force, strong force and strong force. There are approximately 100 billion galaxies in the universe and each … Read more
SCATTERING OF LIGHT When the sunlight travels in the Earth’s circle, it is scattered by the particles in the atmosphere. Light of shorter wavelengths is far more visible than that of larger wavelengths. The amount of scattering is inversely proportional to the 4th power of wavelength. (This is called Raleigh scattering.) This is why … Read more
Have you ever wondered why celestial lightning falls and, then what causes it to fall? Why and how does such a loud sound come when lightning falls. So let’s start, When lightning occurs, the temperature of the surrounding air rises to about 28,000°C within an instant. This temperature is about five times higher than the … Read more
Constellation A group of stars appears to give the appearance of a particular shape when viewed from the earth. Our ancestors conceived some shapes in many names are known as a constellation. These constellations are named on the basis of their shape. For example- Ursa major Ursa Minor Orion Cygnus Hydra … Read more
Photocell The photocell (light cell) is a craft technological application of the photoelectric effect. The photocell is a device that converts light energy into electrical energy. It is sometimes called the electric eye. A photocell consists of a semi-cylindrical light-sensitive metal plate C (emitter) and a wire loop (loop) A (collector) mounted in a vacuum … Read more
