Wave Behavior Relfection Refraction Diffraction Reflection n Reflection

Wave Behavior Relfection, Refraction, Diffraction.

Reflection n Reflection occurs when a wave strikes an object and bounces off of it. n All types of waves including sound, water, and light waves can be reflected

Reflection When a wave bounces off a barrier or surface it is said to be reflected. How much of the wave that is reflected depends on the impedance between the two mediums. n Impedance describes the difference in densities of the two mediums, the greater the difference in mediums, the greater the impedance. n As the impedance increases, more of the n

Echo n Sometimes when the sound waves hit another object, they reflect off it and come back to you. n Your ears hear the sound again, a few seconds after you first heard your footstep.

Sonar n How does a bat use reflection to find food?

Law of Reflection n The angle formed by the incident beam and the normal is the angle of incidence. n The angle formed by the reflected beam and the normal is the angle of refection. n According to the law of reflection, the angle of incidence is equal to the angle of refection. All reflected waves obey this law.

Types of Reflection

Refraction n When a wave passes from one medium to another such as when a light wave passes from air to water it changes speed. n If the wave is traveling at an angle when it passes from one medium to another, it changes direction, or bends, as it changes speed.

Glass and light

Refraction n Refraction is the bending of a wave caused by a change in its speed as it moves from one medium to another.

Sound refraction n n Sound wave will refract if there is a difference in air temperature. The different densities cause the waves to bend.

Snell’s Law n n n 1: index of refraction for incidence medium q 1: angle of incidence n 2: index of refraction for refractive medium q 2: angle of refraction _________________________________ n n Speed of an EM wave in a Medium v = c/n The index of refraction is defined as the speed of light in vacuum divided by the speed of light in the medium.

Critical Angle n The angle of incidence that produces total internal reflection.

Interference n When waves appear at the same point in space and time and combine. Constructive Destructive (superposition)

Diffraction n Diffraction occurs when an object causes a wave to change direction and bend around it. n Diffraction and refraction both cause waves to bend. The difference is that refraction occurs when waves pass through an object, while diffraction occurs when waves pass around an object.

Diffraction