lab9 [Physics Labs]
In a plane mirror, angle of incidence = angle of reflection As stated by law of the effect of the indices of refraction upon the critical angle. An inspection of the data above reveals that there is no clear linear relationship between the angle of incidence and the angle of refraction. For example, a. The angle of incidence and angle of refraction are denoted by the following There is a mathematical equation relating the angles that the light rays make with .
Instead of continuing to go in that same direction, it's going to bend a little bit. It's going to go down, in that direction just like that.
And this angle right here, theta 2, is the refraction. That's the refraction angle. Or angle of refraction.
Angle of Incidence - Incident Ray, Angle of Refraction, Snell's Law | BYJU'S
This is the incident angle, or angle of incidence, and this is the refraction angle. Once again, against that perpendicular. And before I give you the actual equation of how these two things relate and how they're related to the speed of light in these two media-- and just remember, once again, you're never going to have vacuum against water, the water would evaporate because there's no pressure on it and all of that type of thing.
But just to--before I go into the math of actually how to figure out these angles relative to the velocities of light in the different media I want to give you an intuitive understanding of not why it bends, 'cause I'm not telling you actually how light works this is really more of an observed property and light, as we'll learn, as we do more and more videos about it, can get pretty confusing.
Sometimes you want to treat it as a ray, sometimes you want to treat it as a wave, sometimes you want to treat it as a photon.
But when you think about refraction I actually like to think of it as kind of a, as a bit of a vehicle, and to imagine that, let's imagine that I had a car. So let me draw a car. So we're looking at the top of a car. So this is the passenger compartment, and it has four wheels on the car. We're looking at it from above.
And let's say it's traveling on a road. It's traveling on a road. On a road, the tires can get good traction. The car can move pretty efficiently, and it's about to reach an interface it's about to reach an interface where the road ends and it will have to travel on mud.
It will have to travel on mud.
Now on mud, obviously, the tires' traction will not be as good. The car will not be able to travel as fast. So what's going to happen? Assuming that the car, the steering wheel isn't telling it to turn or anything, the car would just go straight in this direction. But what happens right when--which wheels are going to reach the mud first?
This wheel is going to reach the mud first.
Angle of Incidence
There's going to be some point in time where the car is right over here. Where it's right over here. Where these wheels are still on the road, this wheel is in the mud, and that wheel is about to reach the mud. Now in this situation, what would the car do? What would the car do? And assuming the engine is revving and the wheels are turning, at the exact same speed the entire time of the simulation. Well all of a sudden, as soon as this wheel hits the medium, it's going to slow down.
This is going to slow down.
But these guys are still on the road. So they're still going to be faster. So the right side of the car is going to move faster than the left side of the car.
You see this all the time.
Snell’s Law - Higher tier
If the right side of you is moving faster than the left side of you, you're going to turn, and that's exactly what's going to happen to the car. The car is going to turn. It's going to turn in that direction. And so once it gets to the medium, it will now travel, it will now turn-- from the point of the view from the car it's turning to the right. But it will now travel in this direction.
BBC - GCSE Bitesize Science - Radiation : Revision, Page 5
It will be turned when it gets to that interface. Now obviously light doesn't have wheels, and it doesn't deal with mud. But it's the same general idea. When I'm traveling from a faster medium to a slower medium, you can kind of imagine the wheels on that light on this side of it, closer to the vertical, hit the medium first, slow down, so light turns to the right. If you were going the other way, if I had light coming out of the slow medium, so let's imagine it this way.
Let's have light coming out of the slow medium. And if we use the car analogy, in this situation, the left side of the car is going to-- so if the car is right over here, the left side of the car is going to come out first so it's going to move faster now. So the car is going to turn to the right, just like that. Be sure not to move the mirror during this part of the experiment or you will have to begin again.
Draw a single large dot approximately 5 inches in front of the mirror. Shine the laser through the dot, towards the mirror. Make a mark where the laser reflects off of the mirror and another somewhere along the exiting beam. Connect the points to draw the path followed by the light in the reflection process. Draw both the incident and reflected beams.
Do this three more times, pointing the laser at different angles, but still passing through the single dot. Select one of the light paths, measure the incident and reflected angle and find the difference.
Extend the reflected beams backwards, on the other side of the mirror. The point of intersection is the position of the image. This is what your brain does when forming an image. This makes it appear the light came from a point behind the mirror.
Find the percent difference between the distances of the object and image. Remember, object distance p is measure from the object to the incident surface and the image distance q is measured from the incident surface to the image. On your drawing, identify the angle of incidence and the angle of reflection, the object, and the image. How should the angles compare?
Is the image real or virtual? How can you tell? Call over a TA or instructor and explain your conclusion to them. Have your ID card ready to scan to receive credit for your explanation. Snell's Law Figure 7 Draw a set of perpendicular lines on an 8.
Fill the plastic semi-disk container with water and place it so that the flat side is centered along the 8. Mark the point where the light exits the semi-cylinder on the curved side. There are three rays that appear to be exiting the water.
The ray that is directly opposite the incident ray without bending is the beam that is going over the water; you ignore that one. We have already learned that the speed is related to the optical density of a material that is related to the index of refraction of a material. Of the four materials present in the above diagram, air is the least dense material lowest index of refraction value and diamond is the most dense material largest index of refraction value.
Thus, it would be reasonable that the most refraction occurs for the transmission of light across an air-diamond boundary. In this example, the angle of refraction is the measurable quantity that indicates the amount of refraction taking place at any boundary. A comparison of the angle of refraction to the angle of incidence provides a good measure of the refractive ability of any given boundary.
For any given angle of incidence, the angle of refraction is dependent upon the speeds of light in each of the two materials. The speed is in turn dependent upon the optical density and the index of refraction values of the two materials.
There is a mathematical equation relating the angles that the light rays make with the normal to the indices plural for index of refraction of the two materials on each side of the boundary.