# Physics

Topics: Light, Rainbow, Refraction Pages: 2 (834 words) Published: March 3, 2013
1.Properties of light
Reflection
The speed of light is measured through the equation: v = λ f. However, it turns out that when light is reflected off a surface its speed stays the same. This was first proven by Sir Isaac Newton. Under the assumption of perfectly elastic collision, the laws of reflection follow from the laws of motion. To demonstrate, consider a particle traveling towards a flat frictionless surface whose horizontal and vertical velocity components are: VX and VY. When the particle is reflected from the surface there is no change in VX. The vertical velocity component is reversed in direction because of the reactive force of flat frictionless surface. The magnitude of VY is not changed. Since the collision between the particle and the surface is perfectly elastic there is no change in kinetic energy. This also been proven before by measuring the two variables before and after reflection. In order to change the speed of light, either the frequency or the wavelength has to change. The results have shown equivalent values for both of the variables. Thus indicating and proving that the speed of light stays the same after being reflected off a surface. Refraction

Refraction is the bending of light through a substance. Different substances bend light at different angles. White light is made up of a full spectrum of colors. Each color has a different wavelength, and bends at a different angle. This is the same effect that produces rainbows in the atmosphere. The most common illustration of this is a glass prism. When light enters a material such as glass, the light slows down. That’s because the electric charges in the material delay a light wave by interacting with the wave’s electric and magnetic fields. The higher the frequency of the light wave, the more it interacts with the charges in most materials and the more that light wave slows down. Thus high-frequency violet light slows more than low-frequency red light as the two enter a piece of...