Light Fundamental Properties Fundamentals of Light Light is

Light Fundamental Properties

Fundamentals of Light • Light is radiation, which we can see. • Light is only a small portion of the electromagnetic spectrum, which encompasses radiation from gamma rays to radio waves • Light DOES NOT require a medium!

Fundamentals of Light • Light is the range of wavelengths in the electromagnetic spectrum between 400 nm (4 x 10^(-7) m) and 700 nm (7 x 10^(-7) m) • nm = nanometer = 10^-9 m • A ray is a straight line that represents the path of a very narrow beam of light

Fundamentals of Light • Electromagnetic radiation is carried by particles called photons, which have a wave-like nature, and a particle like nature • Photons can be modeled with transverse waves, and can be modeled as point particles

Fundamentals of Light • Electromagnetic radiation comes from accelerating charges, or electrons changing their energy level within an atom.

Fundamentals of Light • Light has an absolute speed. We use the variable c as the constant for the speed of light • c = 3 x 10^8 m/s = 300, 000 m/s

Fundamentals of Light • A light year is the distance light travels in one year • To convert: • 1 light year X 365 days/year X 24 hours/day X 60 min/hour X 60 sec/min X 3 x 10^8 m/sec • 1 light year = 9. 5 x 10^15 m

Fundamentals of Light • Video on the measurement of the speed of light • Then a video on the Michaelson experiment

Fundamentals of Light •

Fundamentals of Light • Example 1: Find the distance to the nearest star if it is 4. 2 light years away (Proxima Centauri)

Fundamentals of Light • Example 2: One star is 10 times further than another. It is also 50 times brighter than the other. What is the ratio of the fluxes?

Fundamentals of Light • Do the worksheet • Homework is pg 332 1 -5 • DUE 2/24/16

Fundamentals of Light • Objects that are transparent allow light to pass through them. • The atoms absorb and transmit the light so it passes through the material. • Objects that are opaque do not let light pass through them. • The atoms in these materials absorb the light as kinetic energy instead of letting it pass through.

Fundamentals of Light • Transverse waves can oscillate up and down, or left and right. • The wave is therefore said to be polarized in that direction • The polarization depends on the direction of vibration the electron has. Vertically oscillating electron = vertically oscillating photon • Sunglasses can filter out light of a particular polarization, making it dimmer

Fundamentals of Light • Polarized light have vibrations that occur in one plane (vertical or horizontal), non polarized light has light which has multiple types of polarization • 3 D glasses have lenses with different polarizations, which creates the illusion of 3 D images!