 # CP Physics Ms. Morrison.  Pitch: a person’s impression of a sound’s frequency  Infrasonic: sounds below 20 Hz  Ultrasonic: sounds above 20,000 Hz 

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CP Physics Ms. Morrison

 Pitch: a person’s impression of a sound’s frequency  Infrasonic: sounds below 20 Hz  Ultrasonic: sounds above 20,000 Hz  Compression: high pressure region of the sound wave, medium pushed together  Rarefaction: low pressure region of the sound wave, medium spreads out  Loudness: a person’s impression of sound intensity (proportional to wave’s amplitude)

 Forced vibration: vibration of an object caused by contact with another vibrating object  Natural frequency: frequency at which minimum energy needed to make the material of the object vibrate and requires the least amount of energy to continue the vibrations  Resonance: when the forced vibration of an object matches its natural frequency and causes a dramatic increase in the amplitude  Beat: difference between the frequencies of two sounds heard together

 Longitudinal  mechanical

 It must vibrate

 20 – 20,000 Hz

 Speed of sound at 0 o C = 331 m/s  Speed of sound at 20 o C = 343 m/s

 It increases – this is because the particles move faster and faster and transfer the wave energy more quickly.

 Solids  Liquids  Gases

 Decibel (dB) – logarithmic scale

 Swinging on a swing  Musical instruments  Opera singer shattering a glass  Bridge vibrations

 A reflected sound wave

 Bats –echolocation  Sonar  Ultrasound  Seeing unborn babies  Examine heart  Uses Doppler shift

a. Brass: musician’s lips b. Reed: reed c. String: string against a sounding board d. Other (flutes): air column within the instrument

 Constructive interference – in phase – causes sound to become louder  Destructive interference – out of phase – causes sound to become softer

 The speed of light is one million times faster than the speed of sound.  343 m/s vs. 3 x 10 8 m/s

 Transparent: material transmits light through it (can see through it)  Translucent: material scatters the light it transmits (can see light but not through it, frosted windows)  Opaque: material does not transmit light, cannot see through it or see light through it  Quantum theory: energy given off as bundles of light energy called photons, explains how light interacts with matter

 Dual theory: light moves through space as a wave and interacts with matter as a particle  Luminous: object gives off light, ex. Sun, lights, fire flies  Illuminated: object reflects light, ex. Moon, mirror  Photon: particle of light energy

 Radio waves  Microwaves  Infrared  Visible light  Ultraviolet  X-rays  Gamma

 Radio waves: radio and TV (longest λ, lowest frequency, and least energy)  Microwaves: heating food  Infrared: heat waves, used in heat lamps, night vision goggles, remotes  Visible light: smallest part of EM spectrum, colors of light  Ultraviolet: causes skin damage – sunburns, can kill bacteria (on fruits and vegetables)

 X-rays: used to see teeth and bones for medical purposes, airport security  Gamma rays: used for radiation therapy, given off in nuclear explosions (shortest λ, highest frequency, most energy)

 Red  Orange  Yellow  Green  Blue  Violet

 Its frequency  Higher frequency = more energy  Lower frequency = less energy

 Illuminated: moon  Luminous: sun

a. reflect: light bounces of boundary of a new medium b. Refract: light bends as it moves from one medium into another medium (air into water) c. Diffract: light passing through small opening spreads out on other side d. Interfere: passing through 2 slits interferes and produces light bands (constructive) and dark bands (destructive)

 Photosynthesis  Absorb light to create electric current (solar calculators)  Absorb light energy then release as color of light

 Light can only pass through in one direction – parallel to material’s polarizing axis  Use polarized filter and turn 90 o to see if light is blocked out

 Red  Green  Blue

 Cyan  Magenta  Yellow

 Two colors that produce white light when they are added together (primary light color + secondary light color)  Red + Cyan  Green + Magenta  Blue + Yellow

 White light is seen when all colors reflected  Black is seen when all colors absorbed

 Magenta light: red + blue  Yellow light: red + green  Cyan light: blue + green

 Light colors = additive process  Pigments = subtractive process

 Pigments absorb some colors of light and reflect the remaining colors of light

RGB G B Color seen is BLACK

RGB Y R Color seen is RED

R G B Y C Color seen is GREEN

RG B C Color seen is BLUE

RG B G M Color seen is BLACK

t = 6.4 sv = d v = 335 m/s t d = ? 335 = d 6.4 d = (335)(6.4) d = 2144 ÷ 2 d = 1072 m

t = 7.2 sv = d v = 340 m/s t d = ? 340 = d 7.2 d = (340)(7.2) d = 2448 m

λ = ?v = λ f f = 375 Hz 530 = λ (375) v = 530 m/s 375 375 λ = 1.41 m

v s = 25 m/sf’ = f (v + v d ) f = 325 Hz (v – v s ) v d = 0 m/sf’ = 325 (343 + 0) v = 343 m/s (343 – 25) f’ = ?f’ = 325 (1.08) f’ = 351 Hz

v s = 0 m/sf’ = f (v + v d ) f = 288 Hz (v – v s ) v d = 32 m/sf’ = 288 (343 + 32) v = 343 m/s (343 – 0) f’ = ?f’ = 288 (1.09) f’ = 313.92 Hz

528 – 520 Hz = 8 Hz

10.5 yrs (365d/y)(24h/d)(3600 s/h) = 3.31128 x 10 8 s = t v = 3.0 x 10 8 m/s d = ?v = d/t d = vt d = (3 x 10 8 )(3.31128 x 10 8 ) d = 9.93 x 10 16 m

t = 180 sv = d/t v = 3 x 10 8 m/sd = vt d = ?d = (3 x 10 8 )(180) d = 5.4 x 10 10 m

d = 1.081 x 10 11 m v = 3 x 10 8 m t = ?v = d/t t = d/v t = 1.081 x10 11 3 x 10 8 t = 360.33 s

λ = ?v = λ f f = 94.1 MHz 3 x 10 8 = λ (94.1 x 10 6 ) = 94.1 x 10 6 Hz 9.41 x 10 6 94.1 x 10 6 v = 3 x 10 8 m/s λ = 3.19 m

λ = 620 nmv = λ f = 620 x 10 -9 m3 x 10 8 = 620 x 10 -9 f v = 3 x 10 8 m/s620 x 10 -9 620 x 10 -9 f = ?f = 4.84 x 10 14 Hz

v = λ f λ = 4.90 x 10 -7 m3 x 10 8 = 4.9 x 10 -7 f v = 3 x 10 8 m/s4.9 x 10 -7 4.9 x 10 -7 f = ?f = 6.12 x 10 14 Hz

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