Science: Physics Waves Flashcards
What is a wave?
A wave is an oscillation (move back and forth with regular rhythm) that moves through space transferring energy from one place to another
Definition for Wavelength.
Wavelength (λ): The distance between two matching points on neighbouring waves. Usually measured in meters
What is frequency?
Frequency (f): This is the number of complete waves per second passing a certain point. It is measured in Hertz (Hz)
What is a period?
Period: the time taken for a complete oscillation to pass by a given point. It is a time interval and measured in seconds
Wave speeds defointion.
Wave speed: distance per unit of time that a given wave travels. Waves travel at different speeds in different mediums
speed = frequency x wavelength
What is the Crest and Trough
Crest/trough: The maximum and minimum level of a wave (max->Crest)
What is the Amplitude?
Amplitude (A): This is the height of a wave from the mid-point (Where there is no displacement) to a peak/crest
What is a sound wave? Is it mechanic or electromagnetic? Is it a longitudinal or transverse wave?
Sound waves are both mechanical and longitudinal
They are mechanical in nature because they require a medium to travel through. They cause matter to vibrate
Sound waves are also longitudinal because thew matter affected by the wave travels parallel to the wave itself
How does the frequency and amplitude of sound affect it.
The frequency of a sound will determine its pitch
The higher the frequency (Shorter the wavelength) of a sound, the higher the pitch to the human ear
The loudness of a sound depends on the amplitude of the wave
The higher the amplitude, the louder the sound
What is radioactive half life?
The time it takes for half of the material to decay
Regardless of how much you start with, after 1 half-life, half of it will have decayed
Each element decays into a new element
Carbon 14 (C14) decays into nitrogen 14
The half-life of each element is constant
What is the diff between mechanical and electromagnetic waves?
Mechanical waves require a medium
A medium is the matter, or substance, through which a wave is transmitted e.g. water is a medium for ocean waves and air particles are a medium for sound waves
Electromagnetic waves – can travel through matter AND empty space (vacuum)
What is a Medium?
A medium is the matter, or substance, through which a wave is transmitted e.g. water is a medium for ocean waves and air particles are a medium for sound waves
What is a transverse wave? How is the matter of medium affected by each type of wave? Exmaples?
The vibrations in traverse waves go from side to side
The energy is travelling in one direction, with the vibrations moving at a 90˚ angle to the direction the wave is travelling
middle line of the transverse wave is the direction the energy is travelling. The actual matter is travelling ONLY up and down at a 90 degree angle to the energy.
longitudinal waves?
Longitudinal waves have vibrations moving in the same direction that the wave is travelling in
This causes particles of matter to move back and forth in the same direction in which he wave travels
Examples of longitudinal waves are: sound waves, a slinky, and p-waves which are the primary waves are produced by earthquakes and which shake solid and liquid matter in the direction they are travelling
Longitudinal waves move matter back and forth raather than up and down.
Law of Reflection
When a light ray hits a mirror it changes direction: The ray is reflected
Angle of incidence (I) = angle of reflection
