Notebookerrs Blog

What is Color You look at the blue sky and feel mesmerized. The same blue sky turns Redding during sunset. amazing!! Sometimes this question comes in our mind, what exactly is this “ Blue “ or this “ Red “. What is “ Color “ actually ? Well color is nothing but Light. This can be reflected light or emitted. Some objects have their own Light, they emit light. For example, the sun is emitting light, the screen of your Computer or Mobile is emitting light. You can see them in the dark. Some objects don't have their own light, they just reflect light. Most of the things around us are reflecting light. Like, an apple looks red because when sun Light gets on the apple it absorbs some light and reflecting only “red” lights. Or your T-shirt is green because your T-shirt is absorbing most of the sunlight and reflecting only “ green “ color. Interesting thing is, you can't see these objects in the absence of light. You can't see the apple or your T-shirt in the dar...

Mirror is a smooth surface where specular reflection takes place. A flat mirror produces an image of equal size and shape. But other than flat mirror there are Concave mirror Convex mirror Convex Mirror A convex mirror is type of curved mirror which bulges outwards, or to the source of the light. It basically diverge the light, because of this these mirrors are also called diverging mirror. Light rays parallel to the axis of the mirror diverge in different directions. As the surface of the mirror is curved perpendicular to the surface is different on every point that's the reason of divergence. After the reflection the light rays are seems to be coming from a point. This point is called Focus. This point is an imaginary point since it's inside the mirror. The distance of the focus from the surface is half the radius of curvature of the mirror. So bigger the radius of curvature of the mirror, smaller the effect of divergence of light. As the f...

Reflection of light is a phenomenon of bouncing back of light after hitting a surface. When a ray of light falls on a surface some of the light reflects, some passes through the surface (refract) and some gets absorbed by the surface. As of now we are talking about reflection only. When the surface is smooth like mirror or polished metal surface the kind of reflection takes place is called Specular Reflection. 2 things are to be noted here The incident ray, the reflected ray and the normal ( perpendicular ) to the surface lie on the same plane The angle of incidence and the angle of reflection are always equal They are called laws of reflection of light. But if the surface is not smooth like, wall or paper or screen the incident rays reflect in different directions and the light diffuse in the surrounding. This type of reflection is called Diffuse Reflection. Mirror Vs Screen In Mirror Specular Reflection takes place and the reflected ray of ligh...

Street Lamps Street lights are bright yellow in color most of places, the reason behind this is the type of lamps used in streets, Sodium Vapour Lamps How Sodium Vapour Lamps work Sodium Vapour lamps are made of a glass tube filled with inert gas like helium and argon and a small amount of sodium. Two electrodes are placed on the ends of the tube. When a voltage is applied across the electrodes, the inert gas inside the tube ionizes and current starts flowing through it. It creates a pinkish red glow. Because of the flow of current the temperature increases and this caused the sodium to vaporise. The sodium vapor then stabilizes the electric arc and sodium vapor creates a monochromatic yellow light. Advantages & Use Human eyes can detect light from wavelength 390 - 700 nm , and sodium vapor generates light of around 600nm wavelength which is quite useful zone of visibility. That means most of the energy coming out this lamps is in the form of visible light...

In the night we use artificial lights. For this purpose we use different types of devices like Bulbs, Tubes, CFLs, LEDs and so many others. Thought their basic idea is same, converting electrical energy into light energy, these devices achieve this goal using different techniques. Lets have a basic idea how they work. Light Bulbs or Incandescent Bulbs As the name says, Incandescent, "emitting light because of being heated" the basic idea of getting light by heating a resistance. Jule's law says when electric current flows through a conductor it gets heated. The amount of heat will mainly depend upon the current, time of flow and  the resistance of the conductor. So more the resistance more the heat. Thats the reason a high resistance thin wire of tungsten is used as a filament. When current flows through the filament it turns red hot and emits light. The filament needs to be protected from getting oxidized and fused by the environment so it's protected ins...