MODULE 1

• wavelength decreases/frequency inceases/energy increases
• The wavelength of visible light ranges from about 400 nm to 700 nm.
• Visible light - is electromagnetic radiation that can be perceived by the human eye.
• A wave is a disturbance in a medium that carries energy without a net movement of particles.
• PARTS OF WAVE

  
• types of reflection

  
• Reflection is the act of light reflecting back when it hits a medium on a plane
• Refraction is the process by which light shifts its path as it travels through a material , causing the light to bend
• Law of reflection states that, on reflection from a smooth surface, the angle of the reflected ray is equal to the angle of the incident ray.
• The incident and reflected ray are on opposite sides of the nomal line
• Law of refraction, which is also known as Snell’s law, governs the behavior of light rays as they propagate across a sharp interface between two transparent dielectric media.
• Snell's Law


  n₁ sin 0₁ = n₂ sin 0₂
• Polarization occurs when all vibrations occur along one axis (plane) only
• Light waves can be polarized or unpolarised
• Snells Law - The ratio of the sine of the angle of incidence to the sine of the angle of refraction is constant at any given boundary between two different materials.
• Light can be polarized using a Polaroid filter or a Nicol prism
• A polarizer allows only waves with their electric field oscillating parallel to the direction of the polarizer to pass through
• Unpolarised light has its electric field oscillating randomly in any direction perpendicular to the direction of travel
• Polaroid filters allow only certain orientations of light wave to pass through them
• The angle of incidence is the angle that an incoming ray makes with the normal line drawn perpendicularly from the point where the ray hits the surface
• The angle of reflection is the angle that the reflected ray makes with the normal line drawn perpendicularly from the point where the ray hits the surface
• Snells’s law (also known as the Snell-Decartes law, the ibh-Sahl law, and the law of refraction)- is a formula used to describe the relationship between the angles of incidence and refraction , when referring to light or other waves passing through a boundary between two different isotropic media, such as water,glass, or air
• Light travels faster in vacuum than it does in glass because the speed of light depends on the medium through which it passes
• When light enters a denser material, it slows down
• Total internal reflection occurs when light tries to leave a dense material into less dense one at an angle greater than the critical angle
• Total internal reflection is a phenomenon that occurs at the boundary between two mediums, such that if the incident angle in the first medium is greater than the critical angle, the light is totally reflected.
• Electromagnetic radiation is a form of energy emitted by moving charged particles
• Wavelenght is the distance from one crest to the next crest which can be measured in meters
• Frequency is the number of waves that passes by a given point each second
• speed of light - 3x10^8 m/s
• Optics is the branch of physics that studies the behaviour and properties of light including its interactions with matter and the construction of instruments that use or detect it.
• Refraction is bending of the path of a light when it passes from one medium to another of different optical density. Light refracts because its speed changes (whether slows down or speeds up) upon crossing the boundary of two media of different optical densities.
• Index of refraction is the measure of the bending of a ray of light when passing from one medium into another
• vacuum= 1

  air= 1.0003

  water= 1.33

  zircon= 1.92
• Snell’s law is named after the dutch astronomer and mathematician, Willebrord Snell
• Total internal reflection is when light passes obliquely from a denser to a less dense medium.
• Dispersion of light is when a beam of light passes through a glass prism the light separates into a band of colors called spectrum
• Dispersion is due to the refraction and refractive index
• Polarization is the property of certain electromagnetic radiations in which the direction and magnitude of the vibrating electric field are related in a specified way
• Malu’s law states that the intensity of plane-polarized light that passes through an analyzer varies as the square of the cosine of the angle between the plane of the polarizer and the transmission axes of the analyzer