P11 - Wave Properties Flashcards
What do waves transfer?
Energy or information
What are the types of wave?
Mechanical waves that pass through a medium.
Electromagnetic waves which can travel though a vacuum and don’t need a medium.
What is a transverse wave?
All electromagnetic waves are transverse. The oscillations are perpendicular to the direction in which the wave transfers energy.
What is a longitudinal wave?
The oscillations are parallel to the direction in which the wave transfers energy. They can be transverse or longitudinal.
What are the parts of a transverse wave?
Amplitude
Wavelength
Trough
Peak
What are the parts of a longitudinal wave?
Wavelength
Rarefaction
Compression
What is the amplitude of a wave?
The amplitude is the maximum displacement of a point on the wave from its undisturbed position. The bigger the amplitude, the more energy it carries.
What is wavelength?
The distance from a point on the wave to the equivalent point on the adjacent wave.
What is frequency?
The number of waves that pass a fixed point every second.
What is the unit of frequency?
Hertz
What is the period of a wave?
The time taken for each wave to pass a fixed point.
How do you calculate a period (with units)?
Period (seconds) = 1 / frequency (hertz)
What are straight waves called?
Plane waves. They move at the same speed and same distance apart.
What is the speed of a wave?
The distance travelled by each wave every second through a medium.
What is the equation for wave speed?
Wave speed (meters per second) = frequency (hertz) * wavelength (meter)
How do you investigate reflection of waves?
Use a ripple tank. Each ripple is called a wavefront as it is the front of each wave. Use a ruler to create plane waves at a straight barrier. Find out if the reflected waves are always at the same angle to the barrier as the incident waves.
What is refraction?
The change of direction in which a wave is traveling when they cross a boundary between one medium and another.
How do you do a refraction test?
Use a vibrating beam to create plane waves in a ripple tank. Arrange the plate so that the waves cross a boundary between deep and shallow. At a non zero angle to a boundary the waves change speed and direction. If perpendicular to a boundary the waves don’t change direction but speed changes.
What happens when a plane wave crosses a boundary at a non zero angle
Change in speed and direction
What happens as a wave travels through a substance?
The amplitude of the waves gradually decreases as the substance absorbs some of its energy.
What are sound waves?
Longitudinal
Can sound waves travel through a vacuum?
No
How do you calculate echo speed?
Speed = distance to the wall and back / time delay
How do you investigate waves?
The oscillator send waves along a string and it send out sounds waves into the surrounding air.
