Power of Lens
Power of the lens is defined as the ability of the lens to converge or diverge the ray of light passing through it. The power of the convex lens is said to be more, if the ray of the light converges more strongly towards the optical center. The power of the lens depends on the focal length of the lens. It is defined as the reciprocal of the focal length in meters. It is expressed as \[P=\frac{1}{f}\].
The SI unit of power of the lens is diopter and is denoted by D. One diopter is defined as the power of the lens having focal length of one meter. The focal length of the convex lens is positive so the power is positive and that of the concave lens is negative as its focal length is negative. more...
Lens
A transparent object having two refracting surface is called lens. It is of two types, concave lens and convex lens. Working of lens is based on the refraction of light passing through it.
Convex Lens
Convex lens is the lens which is thicker at the center and thinner at the edge. It has two refracting surfaces. It is also called the converging lens as the ray of light converges at a point after refraction. The point, at which ray of light converges after refraction, is called the focus of the lens.
Concave Lens
It is the lens which is thinner at the center and thicker at the edge. It also has more...
Refraction of Light
We know that light always travels in a straight line and never changes its direction. But this fact is true as long as it travels in one medium. As soon as it changes its medium i.e. as it goes from one medium to another, it changes its direction at the border of the two medium. This change in the direction of light as it goes from one medium to another is called refraction of light.
For example, when light travels from air to glass, glass to water, water to air, etc it undergoes refraction. Let us consider a rectangular glass slab ABCD as shown in the figure given below. A ray of light PQ is incidented on the glass slab from air at the point Q. The incident light passes through the glass slab. Since the glass slab more...
Image Formation by a Concave Mirror
In this part we will discuss about the nature, position, and relative size of the mage formed of the various position of the objects. The image may be re a or real or virtual. We will try to find out, with the help of a mirror, the position of the objects. The nature of image formed depends on the position o the object the position carnage is obtained by intersection of at least two of the reflected rays.
When the Object is at Infinity
When the object is at infinity, in the case of a concave mirror, the image formed has the following properties:
Image formation by a convex mirror
When the object is placed between P and F
When the object is placed in front of convex mirror, the image formed has following properties:
| S. NO. | Position of Object | more...
 Objects and Images
In this chapter we will use the term objects and image more often. Here the objects refers to the sources of light, which falls on the mirror and reflection takes places. It may be of two types, i.e. either very small or very large. The very small objects are called the point objects. The other term is the image which is obtained when the ray of light from an objects is reflected from a reflecting surface and an object like appearance is obtained. Image is of two types: real image and virtual image.
The real image are the images which can be obtained on the screen. For example the image which we see on the screen of the cinema hall is a real image. The image which cannot be obtained on the screen are called the virtual image. For more...
 Reflection of Light
Whenever light falls on an object some of it is reflected and others are absorbed by the surface. If the light is not reflected by the surface, i.e. all the light is absorbed by the surface, then the object will appear black, like black board or black hole, which is not visible to us. If the light falls on a polished surface, it gets reflected back in the same plane from where it is incidented. This bouncing back of light, after striking a polished surface, is called reflection of light.
Silver metal is considered to be one of the best reflector of light.
Reflection of light shows the particle nature of light. For example, when a rubber cricket ball is strike against a wall it bounces back in the opposite direction, or in other words it is more...
 Introduction
Whenever we hear the word light, many questions arises in our mind. But the most common question that comes in our mind is 'what is light?'. Why we are able to see the object in presence of light and not in the dark? What makes the things visible to us? And many such questions keeps wondering in our mind.
Light is can be defined as the form of energy which produce the sensation of vision. Whenever the light falls on a object it gets reflected by the object and received by our eyes, therefore enable us to see that object. There are many wonderful phenomenon associated with the light, such as image formation, refraction of light, twinkling of star, rainbow formation just after rain, etc. In this chapter we will discuss about all these phenomena associated with the light, more...
Articles CategoriesArchive
Trending Articles
You need to login to perform this action. |
