1. Inverse square law If you double the distance, the effect diminishes by 4 (2 squared) If you triple the distance, the effect diminishes by 9 (3 squared) If you quadruple the distance, the effect diminishes by ____ (___ squared) If you quintuple the distance, the effect diminishes by ____ (___ squared) What types of physical phenomena can be described with the inverse square law? _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Conceptual Physics Reference Sheet: 5/9/14 https://www.youtube.com/watch?v=JW3tT0L2gpc

4. Key characteristics of waves Wavelength Node Amplitude Antinode Amplitude: The height of the wave from node to antinode (transverse waves), or the distance between compression and rarefaction in a in a compressive wave. Measured in units describing the wave Antinode: The extreme point of the wave (max or min amplitude) Wavelength: The distance traversed by a full cycle of the wave Node: The “zero point” of the wave Frequency: The rate of occurrence of the wave (in Hertz or cycles / second) Period: The time between successive waves

5. Speed of Waves where v is the speed, f is the frequency, and lambda is the wavelength. Example of what happens when you change the speed! v = f  The relationship between wave speed, wavelength, and frequency is simple For a given temperature, pressure, material, etc.

6. Conceptual Physics Reference Sheet: 5/9/14 Doppler Effect: When the source of sound (or the hearer of the sound) is moving, the waves in front of the source “bunch up” and the waves behind the source spread out. The frequency goes up in front and gets lower behind the source as it goes by. Fire Siren Sonic Booms Train Doppler More train

7. Conceptual Physics Reference Sheet: 2/29/12 Reflected wave Incident wave “Normal” Reflection Law of Reflection: The angle of incidence equals the angle of reflection, as measured from the normal. Incident rayReflected ray Normal rr ii

8. Conceptual Physics Reference Sheet Refraction FAST SLOW “Normal” What makes lenses work?

9. n = index of refraction rr ii ii Refraction https://www.youtube.com/watch?v=yfawFJCRDSE https://www.youtube.com/watch?v=zTx7UoPXvr4 Light slows down in here!