C.3 - Reflection, refraction and diffraction Flashcards
What are wavefronts?
Imaginary surfaces that connect points on a wave that are in phase
The distance between wavefronts is the _
wavelength
What are rays?
Show the direction of energy transfer as well as the direction of propagation
What is reflection?
When a wave hits a boundary between two media it can bounce off the boundary. This is reflection.
What is the law of reflection?
Angle i = Angle r
What is refraction?
The change in direction of a wave when it moves from one material to the next at an angle. Bending occurs due to differences in density between the mediums and since the velocities in the two mediums are different, the rest of the wave also bends.
What is diffraction?
Spreading out of a wave when it passes through a small gap. The amount of diffraction depends on the size of the gap and the wavelength.
The greater the refractive index, the more the light _ _.
slows down
What is the refractive index?
A measure of how much a medium can slow down light waves. The ratio of the speed of light in a vacuum upon the speed in the medium. n = c/v
What is Snelll’s law?
n1/n2 = sin θ2/sin θ1 = v2/v1
When the angle of reflection reaches 90 degrees, the angle of incidence is known as the _ _.
critical angle
When the angle of incidence is greater than the critical angle, the light is _.
reflected
Conditions for total internal reflection?
Light must be passing from a medium with a higher refractive index to a medium with a lower refractive index, i>c
What are wave pulses?
Short-duration, single oscillations.
What is superposition?
When two wave pulses, travelling in opposite directions pass through each other, their displacements add together at every point in space to produce a combined wave pulse.
