Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
13 Cards in this Set
- Front
- Back
|
What is the speed of a wave affected by? |
the medium it is travelling through |
|
|
What happens to waves in shallow water? |
they slow down and get closer together/ the wavelength gets shorter |
|
|
What stays the same when waves change medium? |
the frequency cannot change |
|
|
Describe refraction? |
when waves hit a boundary between 2 materials at angle they change direction |
|
|
How is a convex lens shaped? |
thicker in middle, thinner at edges |
|
|
How does a convex lens work? |
-light enters and deviates towards normal -when leaving the light deviates away from the normal but the shape of the lens turns the light inwards -light rays all converge on focal point |
|
|
How do you calculate the power of a lens? |
1 --------------------- focal length (m) |
|
|
What are extended objects? |
when astronomical objects look larger then a point eg. Galaxies, Sun, planets, moons |
|
|
Describe the objective lens of a telescope? |
-low power -long focal length -large diameter |
|
|
Describe the eyepiece lens of a telescope? |
-high power -short focal length -magnify's image from objective lens |
|
|
What is the law of reflection? |
angle of reflection is equal to angle of incidence |
|
|
What are the advantages of concave mirrors over convex lenses? |
-lighter and easier to support -easier to manufacture -mirror can be supported along its rear side a lens can only be supported on edge -do not have chromatic abberations |
|
|
What causes chromatic abberations? |
different colours of light are refracted different amounts so image appears coloured |
