U1 - General wave properties (P2) Flashcards
Def: Wavefront
line joining points that are in phase on the same wave
Def: Speed
rate of change of distance, distance a wave travels per minute
Def: Frequency
num of cycles a wave makes per second, measured in hertz
Def: Period
time it takes for a complete wave to pass a point
How do you calculate Frequency
f = 1/ T
Calculate speed
v = f x wavelength
or
v = wavelength/T
How do you calculate wavelength
Wavelength = v/f
Calculate period
T = 1/f
Wavefronts can undergo 3 stages
Reflection
Diffraction
Rafraction
Explain Reflection
when wave meets an object through which it cannot travel, it will be sent back in the direction it came from
Explain Diffraction
the bending effect that occurs when a wave meets an obstacle or has to move through a small space
Explain Refraction
the change in direction of a wave when it travels into a medium that makes the wave travel at a diff speed
What happens when a wave strikes a straight barrier
reflected plane waves are produced
What happens when a circular wave hits a straight barrier
The reflected waves will spread out from a point behind the barrier. The reflected waves are circular and have a centre that’s an equal distance behind the barrier, creating a virtual image of the source
What is a demonstration of a wavefront
the reflection of a circular wave against a straight barrier
what does frequency depend on
the source of the wave
Can the frequency change if it enters a region where it travels more slowly
No
Frequency NEVER changes
What happens to the wavelength of a wave if it enters a region where it travels more slowly
Wavelength will decrease
When do waves move slowly
when it enters shallow water
What happens when waves move from shallow to deeper water
the waves change direction , bending away from the normal when they pass from shallow to deeper water
Why do waves change direction when entering shallow water
Bc. they move slower
Lines of waves in shallow VS deep water
shallow waves - lines are closer together
deep waves - lines have more spaces between each other
Refraction is a demonstration of
waves moving through water from shallow to deep
What happens when straight waves use small gaps
they tend to spread out. the larger the wavelength in relation to the size of the gap, the more the waves will spread out
Diffraction is a demonstration of
straight waves using small gaps
