Do Now: Quiz Prepare for the following quiz by taking out a fresh piece of paper. There will be justifications and the topics span all of waves/light to date.

1. A typical microwave oven produces radiation at a frequency of 1 1. A typical microwave oven produces radiation at a frequency of 1.0 × 1010 hertz.  What is the wavelength of this microwave radiation? 1. 3.0 × 10-1 m 2. 3.0 × 10-2 m 3. 3.0 × 1010 m 4. 3.0 × 1018 m 2. When light rays from an object are incident upon an opaque, rough-textured surface, no reflected image of the object can be seen.  This phenomenon occurs because of 1. regular reflection 2. diffuse reflection 3. reflected angles not being equal to incident angles 4. reflected angles not being equal to refracted angles 3. At the instant shown, a cork at point P on the water's surface is moving toward A B C D

Electromagnetic radiation would be classified as 1. a torsional wave 2. a longitudinal wave 3. a transverse wave 4. an elliptical wave

HW: Aim: How do we determine how much light refracts? DO NOW: Name two different media in this picture. What happens to light as it passes from one medium to the other? Offer an explanation as to WHY you are seeing what you see. HW:

The Electromagnetic Spectrum Radio Microwave Infrared Visible Light Ultraviolet X-Rays Gamma Rays Red Orange Yellow Green Blue Indigo Violet Increasing Frequency Increasing Energy Decreasing Wavelength

Refraction Refraction is the BENDING of a wave as is travels from one medium to another. Remember: a wave changes speed when it moves from one medium to another.

Varying EM Wave Speed Depends on the MEDIUM OF TRAVEL The “speed” of a medium depends on its density and is described by its INDEX OF REFRACTION (n) HIGH index = SLOW medium

Determine the speed of light in lucite. Example #2 Determine the speed of light in lucite.

Index of Refraction FACTS The index of refraction is similar to the coefficient of friction. It tells you how easily (quickly) light travels through a substance It has no units The symbol for index of refraction is n The formula for the index of refraction is c is the speed of light in a vacuum (3x108m/s) v is the speed of light in the other medium. The index of refraction is ALWAYS GREATER THAN ONE!

Using the Index of Refraction In which medium does light move the fastest? In which medium does light move the slowest? In which two mediums will light have the same speed? What is the speed of light in water?

SUMMARY List the properties of EM Waves List the types of waves (from lowest to highest frequency) found in the EM Spectrum List the colors (in order) that make up visible light How can you calculate the speed of an EM wave in a different medium? What is the relationship between the Index of Refraction and the Speed of Light?