P1 5 Waves Flashcards
Transverse waves:
• Transverse waves vibrate at right angles to the direction of the energy transfer of the waves • All electromagnetic waves are transverse waves
What are waves used for?
Waves are used to transfer energy and information.
Longitudinal waves:
• Longitudinal waves vibrate parallel to the direction of the energy transfer of the waves • An example of a longitudinal wave is a sound wave
Mechanical waves:
Mechanical waves need a medium to travel through, these waves may be transverse or longitudinal. Examples of mechanical waves are sound, water and seismic waves.
What is the amplitude of a wave?
The amplitude of a wave is the height of the wave crest or the depth of the wave trough from the position at rest. The bigger the amplitude of the wave, the more energy the wave carries.
What is the wavelength of a wave?
The wavelength of a wave is the distance from one wave crest to the next wave crest.
What is the frequency of a wave?
The frequency of a wave is the number of wave crests passing a point in one second.
Wave speed equation:
Wave speed (m/s)= frequency (Hz) x wavelength (m).
What is the normal on a mirror?
The normal at a point on a mirror is a line drawn perpendicular to the mirror.
Reflection of a light ray by a plane mirror:
• The angle of incidence is the angle between the incident ray and the normal • The angle of reflection is the angle between the reflected ray and the normal
What does the law of reflection state?
The angle of incidence= the angle of reflection.
What is refraction?
Refraction is the change of direction of a wave when it travels across a boundary.
When a light ray refracts from air into glass (less dense to more dense medium), what happens?
The angle of refraction will be less than the angle of incidence, as it refracts TOWARDS the normal.
When a light ray refracts from glass to air (more dense to less dense medium), what happens?
The angle of refraction will be greater than the angle of incidence as the light ray will refract AWAY from the normal.
What is diffraction?
Diffraction is the spreading out of waves when they pass through a gap or round the edge of an obstacle.