Light

What is the speed of light in a vaccum?

299 792 458 m / s or 2.99 x 10^8

What is the speed of light in mms / s?

2.99 x 10^11 mms / s

What is the speed of light in miles per second?

186,000 miles per second

EM_spectrum_compare_level1.jpg

Electromagnetic Spectrum

The shortest Wavelength is Violet and the wavelengths increase as it reaches RED.

ROY G BIV (Red, Orange, Yellow, Green, Blue, Indigo, Violet)

Typically measured in Nanometers (nm) are used as a unit of measure which is 1 billionth of a meter

The Wavelengths are broken into several groups:

Gamma Rays: Less than 10 picometers (one trillionth of a meter, 1×10^-12 meters)

X-Rays: 0.03 nm to 3 nms

Ultraviolet (UV) Rays:

10 nm - 400 nm is UV Radiation

UVc = 290 - 200 nm (absorbed by the o-zone)

UVb = 320 -290 nm (causes corneal burns, retinal damage, sunburns, and eventually cataracts). Absorbed by cornea and crystalline lens.

UVa = 320 - 400 nm (causes sun tan & cataracts, mainly absorbed by crystalline lens)

Visible Light = 400 - 750 nm

Infared (IR) = 700 nm to 1 mm

Microwaves: 1 m to 1 mm (300 MHz to 300 GHz)

Radio Waves: 1 mm to 100 kms (300 GHz to 3 KHz)

FDA requires sunglasses to absorb 95% UVa (5% transmits), 99% UVb (1% transmits). Green focuses upon on the retina, red is beyond the retina, blue is front of the retina. RGB.


Understanding the effect of a polarizer/analyzer also helps us deeply understand where many of the Optical formulas come from. This video by Scholars Wing shows us just how polarization of light works through a polarizer, reflected light, and additional optical equations.

Review:

  1. What is the speed of light in a vacuum in meters per second?

  2. Which color has the shortest wavelength?

    a. Blue

    b. Red

    c. Violet

    d. Orange

    e. Green

  3. UV rays fall in what range?

    a. 10 nm to 400 nm

    b. 400 to 750 nm

    c. 750 nm to 1 mm

    d. 1 mm to 100 kms

    e. less than 1 picometer

  4. Which of the following has the shortest wavelengths?

    a. Polarized Light

    b. Visible Light

    c. UVa

    d. UVc

    e. Infrared

  5. What is the speed of light in miles per second?

Answers:

  1. 2.99 x 10^8 meters per second

  2. Violet

  3. a

  4. d

  5. 186,000 miles per second