| what is a mechanical wave ? | waves that need a medium to propagate in |
| what is a non-mechanical wave ? | a wave that does not need a medium to propagate in |
| what is a longitudinal wave | a wave that oscillated parallel to the direction of the wave |
| what is a transverse waves | a wave that oscillates perpendicular to the direction of the wave |
| what does it mean if two waves are inphase? | 0 phase differences |
| what does it mean if two waves are in anti-phase? | when the waves are half a wave cycle out of phase (180) |
| what is the relationship between intensity and amplitude ? | intensity is proportional to amplitude squared, as amplitude decreases by a factor of 2 then intensity will decrease by a factor of 4 (2^2) |
| what is the saying for refraction? | less to more towards (LESS dense to MORE dense medium results in direction more TOWARDS the normal) |
| what is the principle of superposition? | states that when two or more waves of the same type meet, the resultant wave can be found by adding the displacement of the individual waves |
| what is constructive interference ? | when the displacement of the original waves added together give the resultant waves a displacement that is greater than both the original waves |
| what is deconstructive interference? | when the displacement of the original waves subtract to give the resultant wave a displacement that is less than both original waves |
| what happens if complete deconstructive interference occurs ? | waves completely cancel out resulting is 0 displacement . |
| what conditions must be met for superposition to occur ? | they must be coherent |
| what is a diffraction grating ? | a piece of optical equipment made from glass with many thousands of very thing ,parallel and equally spaced grooves |
| what conditions must occur for a stationary wave to be formed? | 2 waves travelling in the opposite direction overlap. waves having the same frequency m wavelength and amplitude |
| what happens when a stationary wave is formed? | superposition occurs and a series of nodes and antinodes are produced |
| what controls the frequency of the vibrations of a string ? | the mass per unit length, tension and length of string |
| what is a polarising filter? | a material which has crystalline material can cause the oscillating fields to happen in one plane only. |
| what type of waves can be polarised? | only transverse waves can be polarised as longitudinal waves do not have oscillations perpendicular to their direction of their travel. |
| what happens when angle of incidence = critical angle | the wave will travel along the boundary of the material |
