4.3 Wave properties 1 Flashcards
What are the 3 properties of waves?
» Diffraction
» Refraction
» Reflection
What is a ripple tank?
» A shallow transparent tray of water with sloping sides
What is the purpose of slopes on the ripple tank?
» Prevents waves reflection off the sides of the tank
What are wavefronts?
» The waves which are observed in a ripple tank, which are lines of constant phase
In which direction do waves travel in a ripple tank?
» Right angles to the wavefronts
What happens when waves are directed at a certain angle to a flat surface?
» Angle between reflected wave front is same as the incident wavefront
» Direction of reflected wave is the same as the incident wavefront
How are wavefronts actually formed on the piece of paper?
» Wave Crest acts like a convex lens and concentrates the light onto the screen
What happens when the wave changes speed when it hits a boundary?
» Also changes wavelength
What is refraction?
» When the wavefronts approach at an angle to the boundary, they change direction as well as changing speed
Describe what you would observe when a wave changes medium from deep to shallow?
» The wave moves more slowly in the shallow water, the wavelength is smaller in the shallow water so they change direction
Why does light change direction when it moves from air to glass?
» Light moves more slowly in glass
What is diffraction?
» When waves spread out after passing through a gap or round in an obstacle
What does a more narrow grip mean?
» The more waves that spread out
What does a more longer wavelength mean?
» The more the waves spread out
Why is a bigger dish a problem?
» Even though a bigger dish, the stronger signal it can receive
» Bigger dish reflects radio waves to a smaller focus, because it diffracts the waves less
» Therefore needs to be aligned more carefully then a smaller dish
