how's the view little kitty well thanks to these new pair of convex and concave lenses to help us explode the wonders of the universe [Music] that's an excellent question hey friends so in today's episode let us learn about these lenses we call convex and concave zoom in so what is a lens in the first place a lens is a transparent glass of plastic with curved sides that can bend light ways as they pass through it and change direction this process of redirection of light rays as they pass from one medium to another is called refraction but how this light will bend depends upon the type of lens that comes in two main forms convex lens and concave lens though both the lenses are bordered by two transparent spherical surfaces but it's fairly easy to set them apart yes in a convex lens the two spherical surfaces are curved outwards while in the case of a concave lens they are curved inwards also a convex lens is thicker in the middle with thinner edges while the concave lens has a thin center with thick edges but the vital question is how do these lenses work well it's due to refraction which as we learned before is the bending of light rays in a certain way this twisting and turning happens in two ways convergence and divergence and what do they mean well for that first we must look into the way both the lenses work now an imaginary ray of light which is also called an incident ray is projected on a convex lens at an angle then from the point of the incidence which is the touching point of the ray and lens we draw a line known as normal now from the point of incidence this ray of light will enter the lens and because the glass is thicker than air it will slow down the rays speed and bend it down towards the normal line now once this refracted ray reaches the other surface of the lens and enters the air again which is less dense than the glass the momentum pushes the light to continue to refract further as it gains back its speed and this time it bends away from the normal line so in short that's how light is refracted by a convex lens over here we saw how a single incident light will act in such a scenario but in reality there are multiple rays of light and when these rays pass through the convex lens they are refracted according to the angle at which they touch the glass further they meet at a common point also known as convergence at a single point or focal point as rays of light continue in a straight line beyond the focal point to project an image on a screen now let's look at the concave lens which works exactly opposite that of the convex lens yes if the incident rays from a point object are projected towards a concave lens then after refraction they do not converge at a single point but diverge meaning they go away from each other and because of this instead of forming the image on the other side these rays extend backward and meet at a certain point behind the lens so a virtual image appears at this focal point your time did you know the distance from the center of the lens to the focal point is called focal length also the focal length of the lens and the distance between the lens and the object will cause the image to be smaller or larger than the original object hope you learned something vital today until next time it's me dr binox zooming out [Music] use this nevermind [Music] you