Zusammenfassung der Ressource
Physics - Reflection,
Refraction, Diffraction
- Reflection
- The image in a plane mirror is
virtual, upright and laterally inverted
- Angle of reflection = Angle of incidence
- The 'normal' is a construction line
perpendicular to the reflecting surface at the
point of incidence
- Rough surfaces scatter sound
and light in all directions
- Smooth surfaces produce strong echoes
when sound waves hit them, and they can act
as mirrors when light waves hit them
- Refraction
- Bending of waves
- When light travels through
another medium, the waves are
slowed down or sped up,
therefore bending it
- The speed of the waves
are changed
- Slows down = bent
towards normal
- speeds up = bent away
from normal
- The ray goes at an angle
towards the normal
- Doesn't happen if the waves
enter the medium at an angle of
90° (the normal)
- They carry straight on
- Angle of refraction
< Angle of
Incidence
- Diffraction
- The spreading out of waves when
reaching (going through) a gap
- The extent of the spreading depends
on how the width of the gap compares
to the wavelength of the waves
- Significant diffraction only happens
when the wavelength is of the same
order of magnitude as the gap
- A gap similar to the wavelength
causes a lot of spreading with
no sharp shadow
- E.g. Sound through a doorway
- A gap much larger than the
wavelength causes little
spreading and a sharp shadow
- E.g. Light through a doorway