Wave Properties Flashcards
Constructive
Two waves combining to produce a maximum
Destructive
Two waves to produce a minimum
Diffraction
The spreading of waves on passing an edge or through a narrow gap
Grating
A sheet of transparent material with fine lines etched on it to produce diffraction; each gap in the grating acts as a coherent source
Interference
A series of maxima and minima produced when waves meet
Maxima
Points of constructive interference
Minima
Points of destructive interference
Path difference
The difference in distance from one source to a point and the other source to the point
Phase
How we describe the relative position of a wave
Coherent
Light with fixed/no phase difference
Waves which are coherent have the same speed, wavelength and frequency and have a constant phase relationship
How bright fringes are produced
By waves meeting in phase/crest to crest/trough to trough
Critical Angle
The angle between the ray of light and the normal at which light striking the glass air boundary will be totally internally reflected
Decreasing the spacing between bright bands
Use of lower wavelength light eg Blue
How a minimum reading is produced
Two waves meet out of phase
What will happen to number of visible maxima if you change the colour of light used to lower frequency
Greater wavelength
Lambda increases causing sin theta to increase
Visible maxima decreases
Describe what is meant by Critical angle
The maximum angle of incidence at which refraction can occur
Why white light produces a spectrum?
Refractive model is different for different frequencies/colours
Use and theory to explain how electrical conduction takes place in a pure semi conductor eg silicon
Fewer electrons in conduction band
Small band gap
Electrons are excited to conduction band
Charge can flow when electrons in conduction band
