waves

IG 第三单元 物理 ，介绍了波的性质、光波和声波、光线的种类等。希望此脑图对大家有所帮助！

waves

properties of waves

wave is a way to transfer energy from a place to other place

wave front

the kinds of wave

longitudinal wave

the direction of vibration is along to the direction of energy transfer

transverse wave

the direction of vibration is at right angle to the the direction of energy transfer

describing wave

frequency : the number of wave produce each second

formula

the dopple effect

when this car is moving, the wave front in the front of the car is compress,the speed of sound is constant, so the frequency of the car increase, the pitch will increase

light waves and sound waves

the kinds of wave

light wave : transvers wave

sound wave : longitudinal wave

how can we see the thing

reflection

应用： persicope

refraction

n=sin i / sin r

calculate the n

total inversal reflection

条件：1.the ray from low infractive index medium to low infractive index medium 2. the angle of i is bigger than critical angle

sin c = 1/n

用途

periscope

reflector

optical fibres

the endoscope

how can we hear the sound

the kinds of ray light

不同光的波前

它们的共同点

the all transfer energy

the speed of ray is 300 000 000 m/s in a vaccum

they all transvers wave

the all can be relection and refraction

不同点及用途与危害

危害

microwave : human body tissue

IR: skin burns

UV: harmful to body's eyes

X rays: cancer

gamma rays: cancer

局限性:光线较暗