Sample Problems for Snell's Law
SparkNotes online free test prep. The law of reflection tells us that angle of incidence and angle of reflection are equal: index of refraction, Snell's Law governs the relationship between the angle of incidence and the angle of refraction. SparkNotes online free test prep. The law of reflection tells us that angle of incidence and angle of reflection are equal: index of refraction, Snell's Law governs the relationship between the angle of incidence and the angle of refraction. Snell's Law Formula | Snell's law is a relationship between the angles of incidence and refraction and the indices of refraction of the two media.
The depth that the water appears to be when viewed from above is known as the apparent depth. This is an important consideration for spearfishing from the surface because it will make the target fish appear to be in a different place, and the fisher must aim lower to catch the fish.
Conversely, an object above the water has a higher apparent height when viewed from below the water. The opposite correction must be made by an archer fish. But, as the angle of incidence approaches 90o, the apparent depth approaches zero, albeit reflection increases, which limits observation at high angles of incidence. Conversely, the apparent height approaches infinity as the angle of incidence from below increases, but even earlier, as the angle of total internal reflection is approached, albeit the image also fades from view as this limit is approached.
An image of the Golden Gate Bridge is refracted and bent by many differing three-dimensional drops of water. Dispersion[ edit ] Refraction is also responsible for rainbows and for the splitting of white light into a rainbow-spectrum as it passes through a glass prism.
Glass has a higher refractive index than air.
When a beam of white light passes from air into a material having an index of refraction that varies with frequency, a phenomenon known as dispersion occurs, in which different coloured components of the white light are refracted at different angles, i. The different colors correspond to different frequencies. The refractive index of air depends on the air density and thus vary with air temperature and pressure. Since the pressure is lower at higher altitudes, the refractive index is also lower, causing light rays to refract towards the earth surface when traveling long distances through the atmosphere.
This shifts the apparent positions of stars slightly when they are close to the horizon and makes the sun visible before it geometrically rises above the horizon during a sunrise. Heat haze in the engine exhaust above a diesel locomotive. Temperature variations in the air can also cause refraction of light. This can be seen as a heat haze when hot and cold air is mixed e. This makes objects viewed through the mixed air appear to shimmer or move around randomly as the hot and cold air moves.
This effect is also visible from normal variations in air temperature during a sunny day when using high magnification telephoto lenses and is often limiting the image quality in these cases. 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.
BBC Bitesize - Higher Physics - Refraction of light - Test
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.RELATION BETWEEN REFRACTIVE INDEX AND CRITICAL ANGLE
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.
Snells Law Formula
The shortest ray you might not see it is the beam going only through the plastic holder; you ignore this beam also. You want the middle length beam; it is the one that went through the water.
Repeat this process for each incident angle. You will have five dots on the curved side of the semi-cylinder so make sure you mark the corresponding incident angle for each one. Remove the container and draw lines through these points and the center of the paper where the perpendicular lines intersect.
These are the refracted light beams. Add a New Calculated Column name the column sin theta t.
General Physics Experiment 9
In Equation box enter: Add a New Calculated Column name the column sin theta i. Click on the y-axis and select sin theta i from the list. Click on the x-axis and select sin theta t from the list. Find the slope of the line. On your drawing, identify the angles of incidence and the angles of refraction. Where do you measure them from? What is the base of the angle?
What would happen to the relative size of the angles of refraction if instead of being a dish of water in air, we had a dish of air underwater. Apparent Depth Figure 5 Draw a set of perpendicular lines on an 8. Place the rectangular plastic plate so that the clear face is centered along the 8.