# Leaving cert physics waves and refraction

 .remove_background_ad { border: 1px solid #555555; padding: .75em; margin: .75em; background-color: #e7e7e7; } .rmbg_image { max-height: 80px; } What is a wave A disturbance that carries energy from one place to another Name the two types of waves longitudinal and transverse Define a transverse wave plus example the direction of the vibration is perpendicular to the energy of the wave e.g waves in waterradio wavesvisible light Define a longitudinal wave plus example the direction of the vibration is parallel to the propagation of the wave sound wavescompression waves on slinky Define period direction of the wave propagation Define electromagnetic waves waves that disturb or vibrate electric and magnetic fields m and e perpendicular to each other and direction What are the 5 wave phenomena reflectionrefractiondiffractioninterferencepolarisation (light only) Interference the addition of two or more waves causing a single resultant wave Coherent waves two waves are said to be coherent if they have the same frequency and are in phase or have a constant phase difference between them Define "inphase" means that crests and crests are directly in line with each other Constructive interference happens when two or more waves combine to give a resultant wave with greater amplitude than the source wave Destructive interference Happens when waves combine and the resulting wave has a lesser amplitude than the source wave Frequency the number of cycles completed at any one point/second unit hertz (Hz) Period of a wave the time taken to undergo one complete cycle The amplitude of a wave the height of a wave wHAT IS THE CREST AND Trough the top and bottom of a wave Why is each fibre coated with glass of lower refractive index?  Because total internal reflection can only occur for rays traveling from a medium of higher to lower refractive index. Explain, with the aid of a labeled diagram, how a ray of light is guided along a fiber. An optical fiber consists of a glass pipe coated with a second material of lower refractive index. 5. Light enters one end of the fibre and strikes the boundary between the two materials at an angle greater than the critical angle, resulting in total internal reflection at the interface. 6.This reflected light now strikes the interface on the opposite wall and gets totally reflected again. 7. This process continues all along the glass pipe until the light emerges at the far end. Diffraction the ability of a wave to spread out after it has encountered an obstacle when waves meet to create interference patterns Diffraction grating consists of transparent material with a large number of parallel lines etched on it Polarisation waves that vibrate only in a single plane dispersion which is the separating of light of the different wavelengths Refraction the way in which light bends when it passes from one medium to another Snell's law n=sin(i)/sin(r) the normal angle of incidence, angle of refraction are all on the same plane Applications of optical fibers endoscopy and telecommunications industry Total internal relflection where light is reflected back from a boundary between two media when the angle of incidence is greater than the critical angle Critical angle the angle of incidence for which the angle of refraction in 90 degrees Power of a lens p=1/f When two or more lenses are in contact 1/f=1/f(1)+1/f(2) Accommodation the process of adjusting the focal length of the lens to focus distant objects near objects clearly on the retina Myopia (short-sight) means distant objects can not be seen clearly Hyperopia (long sight) means near objects can't be seen clearly Which needs a convex lens himage forms behind retinato focus on retina Which needs a concave lens Mlight focused infront of retinaconcave Reflection the bouncing of light rays off the surfaces law of reflection The incident ray, the normal and reflected ray are all on the same plane the angle of incidence is equal to the angle of reflection Example of concave mirrors dentist's mirrors Example of convex mirrors concealed entrancessupermarketscar rear view mirror give diminished view A standing wave is produced when two waves of the same frequency and amplitude meed, moving in the opposite directions Harmonics are multiples of the natural frequency of vibration of  body Resonance the transfer of energy between two bodies of the same natural frequency The intensity of sound at a point the rate at which energy crosses a unit area perpendicular to the direction in which the sound is travelling The frequency limits of audibility The highest and lowest frequency sound waves that the average human can hear .remove_background_ad { border: 1px solid #555555; padding: .75em; margin: .75em; background-color: #e7e7e7; } .rmbg_image { max-height: 80px; } Authorcat126 ID349752 Card SetLeaving cert physics waves and refraction Descriptionwords Updated2019-12-09T18:42:37Z Show Answers