Of the perspective that we're dealing with. Look like they're the same but that's just because Right here- and I know it's hard- it doesn't That's the incident angle relative to vertical. Surface of the water, right before it bounces, Here, that's the angle- Let me do that in a light color. Here, but this angle right over here- Let me draw It's actually coming straightĭraw a vertical, and it might not be that obvious Reflected, specular reflection, to our eyes. The surface of the water, and then it's getting Part of the mountain, hitting this part of the The mountain up here, and the part of the Rays, and they're actually being scattered in everyĭirection, some of them are hitting the water. That's why we don't see theĪctual image of the sun here. And we're going to talkĪbout diffuse reflection in a little bit, and Images of specular reflection, just to make it clear here. See that in a couple of images over here. That you might experience is that the angle This for yourself at all the regular mirrors Right there, we call that the angle of reflection. Show that the angle at which we're coming in, theĪngle between this ray and the vertical right there, Surface of the actual mirror right over here, we wouldĭefine this, right here, as the angle of incidence. So you can think aboutįront of the bathroom mirror you can thinkĪbout this, and think about the angle of incidenceĪnd the angle of reflection.
With mirrors you would see- and we're going to And you may haveĪlready noticed this if you've played around a lot This the reflected ray, after it is kind ofīounced off of the surface. So then it'll hit the surface,Īnd then it'll bounce off, and it'll go just like that. That it bounces off at essentially the same angle,īut in the other direction. Ray because it's the ray as it approaches Terminology right, this light ray coming in, Is kind of what we normally associate with reflection Is doing one or the other, or something in between. Two types of reflection, and everything that reflects I think most of us haveĪ sense of what this is, but we'll try to get a littleīit more exact about it. Going to try to learn a little bit about reflection. When the angle of incidence is greater than the critical angle none of it is refracted, the ray is totally internally reflected, and the law of reflection is obeyed, i = r.In our eyes there are microscopic tiny sensors which are sensitive to light.They have 3 colors red,blue and green.If you look at a very bright thing such as the sun and close your eyes immediately you will see red.This means that red is the most sensitive to light.When you see any light source glowing brightly and when you see it and close your eyes immediately you will see green.In your case you might have seen a brightly glowing bulb.So green is less sensitive to light than red.Finally if you see a light source glowing dimly you will see blue color.So blue is least sensitive to light.One interesting fact for you that when you look at the sun immediately and close your eyes firstly you will see red color.But as the light intensity seen by our eyes decreases you will see green color then and finally you will see blue color and then you will see only black.The order of sensitivity of the receptors are: When the angle of refraction is exactly 90°, then the angle of incidence is called the critical angle C.
The diagram below shows the light refracting from glass into air.įor light travelling from glass into air the angle of refraction is greater than the angle of incidence.
if the angle of incidence in the glass is greater than the critical angle, total internal reflection occurs.if the angle of refraction in the air becomes 90°, the angle of incidence in the glass is called the critical angle.the angle of incidence in the dense medium is greater than the critical angle.light travels from a dense medium to a less dense medium e.g.Total internal reflection only occurs when: The angle of incidence when the angle of refraction is 90 o, and the ray changes from just refracting to total internal reflection, is called the critical angle. This is called total internal reflection (TIR). In this situation, the ray is reflected inside the more dense medium, following the law of reflection. However, if this would bend the ray at more than 90° from the normal, the refraction is not possible. If it is leaving the more dense medium, this refraction would be expected to bend the ray away from the normal as it emerges. When a light ray reaches the boundary between two transparent materials it may be refracted.
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