Leaving cert physics waves and refraction

A disturbance that carries energy from one place to another

longitudinal and transverse

the direction of the vibration is perpendicular to the energy of the wave

• e.g waves in water
• radio waves
• visible light

the direction of the vibration is parallel to the propagation of the wave

• sound waves
• compression waves on slinky

• direction of the wave
• propagation

waves that disturb or vibrate electric and magnetic fields

m and e perpendicular to each other and direction

• reflection
• refraction
• diffraction
• interference
• polarisation (light only)

the addition of two or more waves causing a single resultant wave

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

means that crests and crests are directly in line with each other

happens when two or more waves combine to give a resultant wave with greater amplitude than the source wave

Happens when waves combine and the resulting wave has a lesser amplitude than the source wave

the number of cycles completed at any one point/second

unit hertz (Hz)

the time taken to undergo one complete cycle

the height of a wave

the top and bottom of a wave

Because total internal reflection can only occur for rays traveling from a medium of higher to lower refractive index.

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.

the ability of a wave to spread out after it has encountered an obstacle when waves meet to create interference patterns

consists of transparent material with a large number of parallel lines etched on it

waves that vibrate only in a single plane

which is the separating of light of the different wavelengths

the way in which light bends when it passes from one medium to another

n=sin(i)/sin(r)

the normal angle of incidence, angle of refraction are all on the same plane

endoscopy and telecommunications industry

where light is reflected back from a boundary between two media when the angle of incidence is greater than the critical angle

the angle of incidence for which the angle of refraction in 90 degrees

p=1/f

1/f=1/f(1)+1/f(2)

the process of adjusting the focal length of the lens to focus distant objects near objects clearly on the retina

(short-sight) means distant objects can not be seen clearly

(long sight) means near objects can't be seen clearly

• h
• image forms behind retina
• to focus on retina

• M
• light focused infront of retina
• concave

the bouncing of light rays off the surfaces

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

dentist's mirrors

• concealed entrances
• supermarkets
• car rear view mirror

give diminished view

is produced when two waves of the same frequency and amplitude meed, moving in the opposite directions

are multiples of the natural frequency of vibration of  body

the transfer of energy between two bodies of the same natural frequency

the rate at which energy crosses a unit area perpendicular to the direction in which the sound is travelling

The highest and lowest frequency sound waves that the average human can hear