Flashcards
Light
Flashcards do conjunto (15)
- 1How do we see stuff?When light is emitted by an object or reflects off it that light hits the back of our retina which is then made into an electrical signal which is sent to our brain.
- 2What is the normal line?A dashed line drawn at 90° to the surface of the object
- 3What is the Law of Reflection?Angle of Incidence = Angle of reflection
- 4What is specular reflection?When light reflects off a microscopically smooth surface and reflects at the same angle from the Normal line to the angle from the normal at which it hit the surface
- 5What is diffuse reflection?When light hits a microscopically rough surface and bounces in random directions
- 6What does a diagram to show the formation of images in mirrors look like?
- 7What is a virtual image and how is it different to a real one?A virtual image is an image that the light appears to come from but doesn't actually come from e.g. an image in a mirror. A real image is an image where the light rays do come from
- 8What is refraction and why does it happen?It happens because when light goes through different objects they have different densities so it changes the speed of the light wave slightly. This also causes a slight change in direction
- 9What do the effects of refraction of light do?Refraction of light between water and air cause objects appear closer to the water then they really are. This is why a straw in water can appear bent
- 10What does a convex lens do to parralel rays of light?It causes all the rays of light to meet at a single point called the focal point
- 11What does a concave lens do to parallel rays of light?It makes them all spread apart
- 12What happens to white light when it is shone through a prism?All the different colours spilt apart because they go at different speeds so enter and leave the prism at different angles showing all of them
- 13What is the EM spectrum?A range of transverse waves caused by
charged particles vibrating. They are: Radio waves, Microwaves, Infrared, visible
light, Ultra Violet, X-rays, and Gamma rays. - 14What are the different EM waves used for?Radio waves: Communication. Microwaves: Communication and cooking. Infrared: Heating and communication. Ultra violet: security and fluorescent lights. X-rays: medical imaging and cancer treatment. Gamma rays: medical imaging and sterilisation.
- 15Why are UV, X - rays and Gamma rays dnagerous?They can go through the human body and they can affect the DNA inside it which can lead to mutations or cancer.