Snell's Law In the previous sections we studied light reflecting off various surfaces. What happens when light passes from one medium into another? The speed of light, like that of all waves, is dependent on the medium through which it is travelling. When light moves from one medium into another (for example, from air to glass), the speed of light changes. If the light ray hits the boundary of the new medium (for example the edge of a glass block) at any angle which is not perpendicular to or parallel with the boundary, the light ray will change its direction through the next medium, or appear to `bend'.
Specular vs. Diffuse Reflection - in diffuse, waves are reflected in many different ways form a rough surface - in specular, waves are reflected in the same direction from a smooth surface REFRACTION (light) - when one medium ends and another begins, that is called boundary - when a wave encounters a boundary that is denser, part of it is reflected and a part of it is transmitted - the frequency of the wave is not altered when crossing the boundary / barrier but the speed and wavelength are - the change in speed and wavelength can cause the wave to bend if it hits the boundary at an angle other than 90 degrees - this bending as light enters the water can cause objects under water to appear at a different location than they actually are REFRACTION (sound) - sound waves bend when passing into cooler / warmer air because the speed of sound depends in the temperature of the air - sound travels slower in cooler air REFRACTION (water) - water waves bend when they pass from deep water into shallow water, the wavelength shortens and they slow down. DIFFRACTION - involves a change in direction of waves as they pass through
The attenuation of glass optical fiber is caused by two factors, absorption and scattering. Absorption occurs in several specific wavelengths called water bands due to the absorption by minute amounts of water vapor in the glass. Energy of this type of wave. 3. How is this type of wave created?
The last part of the experiment is to determine the measurement of the diameter of powder spores by passing a monochromatic light source through a circular aperture and producing a diffraction pattern of concentric rings. Theory A diffraction grating consists of a series of opaque and transparent strips. Light passing through the grating is broken up into portions which come through each slit. The light from the various slits interfere with one another producing dark and bright fringes. Bright fringes occur when the path length of the light from adjacent slits to the screen is an integral multiple of the wavelength.
In nearly all bulbs now, the filament is protected from oxidation with the outside by filling the bulb with different gasses or just by causing a vacuum inside the area around the filament. Usually the gas inside a bulb will be Argon as it does not react with other atoms as freely. Even though our atmosphere only contains around 21% Oxygen it would still cause the filament to oxidize and burn at a quicker rate, this would cause the filament to burn out in under three seconds. Incandescent light bulbs are made in a variety of different sizes, power, brightness and efficiency. Despite this filament bulbs still keep their title as a cheap, portable and quick to organize source of light available to nearly everybody who has access to electricity.
It was also concluded, that the experiment was exposed to other factors that affect the rate of diffusion of a substance. INTRODUCTION Liquid and gas substances contain particles that move freely, and are least compact. Following the movement of these particles, it would appear to bounce at random between its collisions with other atoms or molecules. This random movement is called diffusion (Patlack, J. and Watters, C. 1999). Diffusion is the tendency of materials to move from area of higher concentration to areas of lower concentration (Postlethwait, 1995).
As the particle travels through the medium it loses kinetic energy by polarizing the electrons of the given material. These polarized molecules then relax back to equilibrium through the emission of a photon (of ultraviolet or visible light). If the velocity of the particles in the medium is faster than the speed of light in the medium constructive interference occurs and Cherenkov radiation is observed3-4. The luminescent property of Cherenkov radiation is significant as it has been demonstrated this light may be imaged using bioluminescence imaging equipment in vivo. This enables a number of applications including: the visualisation of tumours, radiotracer development and intraoperative guidance among others2.
Experiment on finding the Refractive Index value of Perspex using Snell’s law Aim: The aim of this experiment is to find the refractive index of Perspex, using Snell’s law. By shining a ray at a prism and drawing the incoming and out coming ray, and then drawing the normal and measuring the angles. Variables: Table 1: table of variables Identify the variable(s) How will the variable(s) be changed, measured, and/or controlled? Independent variable(s) Angle of incidence Move the box around so that the ray hits the prism at different angle. Dependent variable(s) Angle of refraction Measure the angle with a protractor.
Heat flows from the warmer to the cooler object until they are both at the same temperature. Conduction is the movement of heat through a substance by the collision of molecules. At the place where the two object touch, the faster-moving molecules of the warmer object collide with the slower moving molecules of the cooler object. As they collide, the faster molecules give up some of their energy to the slower molecules. The slower molecules gain more thermal energy and collide with other molecules in the cooler object.
The earth's atmosphere filters out UVC radiation, but UVA and UVB affect you every day. UVB affects the top layers of skin, while UVA penetrates to the deeper layers. Your hair and your skin are negatively affected by these UV rays, although they appear to react differently. A pigment called melanin determines the color of your skin and hair. One form of melanin is a reddish-yellow color, while the other is brownish-black.