Waves - reflection, transmission and diffraction. Flashcards
Difference between incident ray and reflected ray
Only the direction changes between the incident and reflected ray.
The reflected ray is still travelling in the same medium (because it is the deflection of a wave caused by it hitting an obstacle), so it has the SAME frequency and speed, and wavelength as incident ray.
What is the transmission of a wave
When a wave is able to travel from the first medium into the second medium if the surface that a wave strikes is the boundary between two mediums.
The difference between a transmitted ray and the incident ray
The transmitted ray will have same frequency, but DIFFERENT speed therefore different wavelength.
Difference of amplitude between transmitted ray, incident wave and reflected wave.
Amplitudes of reflected and transmitted rays are less than the amplitude of incident wave, because energy that the wave was carrying has been shared between the reflected and transmitted waves.
What is diffraction?
The bending of a wave around the edge of a barrier.
What does the amount of bending (diffraction) depend on?
The wavelength of the wave. The longer the wavelength, the more it bends around the edge of a barrier.
What happens to rays when it hits a barrier?
The rays untouched by the barrier continues as if the barrier had not been there. At the edge of the barrier, the waves touched bends around into the space created by the part of the wave that has been stopped.
pg 115.
Why do shadows have sharp edges?
Because light waves have a very short wavelength therefore do not bend much after passing the edge of a barrier.
What shape do diffracted rays look like after passing through a narrow gap?
Diffraction occurs at both edges, so very circular.
