T3: waves

• wavelength = the length of one complete wave measured in meters
• frequency = how many waves pass a certain point in one second
• frequency is measured in hertz (Hz)
• we can calculate the frequency if we know how long it takes for one cycle
• wavefronts occur when multiple waves are moving in a straight line, joining the peaks
• the distance between wavefronts represents the wavelength
• when a light reaches a mirror it reflects of the surface
• the incident ray is the light going towards the mirror
• the reflected ray is the light coming away from the mirror
• the law of reflect - angle of incidence = angle of reflection i=r
• refraction is the change in speed of waves when they enter a different medium
• refration can change the dirrection of the wave
• the greater the density = the slower the wave
• incident ray hits another medium at 90 degrees = slows but stays same direction
• incident ray hits different material at a non-right angle = slows and changes direction
• faster = away from normal , slower = close to normal
• the normal is a dotted line at 90 degrees to the surface of the refracting material, where the light enters
• light into denser material = refracts towards the normal
• light into less dense material = refracts away from the normal
• when the wave slows = the wavelength decreases
• when the wave speeds up = the wavelength increases
• the angle of incidence is less than the critical angle = refraction
• the angle of incidence = critical angle - travels along the boundary between the two mediums
• if the angle of incidence is greater than the critical angle = total internal reflection
• fire optics cables carry information into your home and provide internet access
• endoscopes used by profensionals in keyhole surgery use the critical angle
• all waves experience the doppler effect
• the doppler effect occurs when the source of the waves moves relative to the observer
• as the object moves towards the observer = waves catch up to eachother = higher frequency
• as the object moves away from the observer = the waves stretch apart = lower frequency
• object moving towards = higher pitch
• object moving away = lower pitch
• speed of the waves stay the same
• object moving away = wavelength gets longer
• object moving towards = wavelength gets shorter
• longitudinal waves?

  vibrations are parallel to the energy transferred
• transverse waves?

  vibrations are perpendicular to the energy transferred
• amplitude of a wave?

  maximum displacement of a point - height of peak or depth of trough