P5.3 Flashcards
What can you use ray diagrams to do
You can use ray diagrams to show what happens when electromagnetic waves, such as light, hit a surface; or travel through matter.
When you construct a ray diagram what do you do
Draw lines to represent wave
Draw a line (normal) at 90 degrees to the surface at the point where the ray hits it
Measure the angle from the normal to the ray
What happens when light goes from air into glass
When light foes from air into glass at an angle, it slows and bends towards the normal. If the difference in density is larger. Then the change in direction is also larger.
What does what happens to electromagnetic waves depend on
It depends on wavelength
What does a convex lens do
A convex lens has a converging lens refracting rays to a principal focus or focal point.
What does a concave lens do
It diverges light.
How do lenses correct vision
If you have normal vision the cornea and lens of your eye focus light onto your retina to produce a sharp image.
What happens if you have long sight
You can’t focus on nearby objects and short sight you can’t focus on distant objects.
What can you use ray diagrams for
You can use ray diagrams to predict the type, size and position of an image. The type of image. The type of image depends on the positions of the object relative to the lens.
What is the difference between real and virtual image
A real image can be projected on a screen but a virtual image can’t
What are the different ways to describe images
Virtual or real, magnified or diminished, upright or inverted
Why do prisms separate light
Each frequency of light travels at a slightly different speed in glass. Each frequency of light is refracted by a different amount. Colours associated with a higher frequency are refracted more than those with a lower frequency. This spreads out white light into a spectrum. This is called dispersion.
How does your eye see colour
The retina of your eye is sensitive to three of the spectral frequencies: red, green, and blue. Spectral colours trigger different signals in the red, green, and blue receptor cells. Your brain puts together these signals to make perceived colour.
What do different filters do
A red filter absorbs all the different frequencies of white light except the red frequency. No light gets through a red and green filter put together so it looks black.
What do coloured objects do
The coloured objects reflect the colour that it is and absorbs the other colours in the spectrum.
