Light A1 64 – 73 Flashcards
Why cant you see through a translucent object?
Light rays travel through it but they will be scattered so you cant see clearly.
State the speed of light
3 million m/s
What happens during a solar eclipse?
The moon is inbetween the sun and earth, a shadow of the moon appears on the earth, those in the umbra will see a total solar eclipse but those in the penumbra will see a partial one.
What happens in a lunar eclipse.
When the earth is inbetween the sun and the moon, and there is a partial and total lunar eclipse as the moon revolves.
What happens when you shine a light on the mirror.
It refelcts of the surface of the mirror at the same angle it was pointed at.
(ray of incidence) i = r (ray of reflection)
What is the law of reflection?
When a light is reflected from a mirrow, the ray of incidence is equal tot the ray of reflection.
Why don’t you see your reflection of a piece of paper?
Because light reflects off in scattered directions since its a rough surface.
What is reflection off a smooth surface?
Specular reflection
eg: A mirro’s reflection
What is a reflection off a rough surface?
Diffuse reflection
How should light reflect to see a reflected image?
It should reflect off the same directions in parallel lines, they shouldnt scatter off in different directions.
What is refraction?
Refraction is the change in the direction of a ray passing from one medium to another because of varying density.
What are the two types of lenses?
Convex and concave
How do convex lenses work?
The lense reflects light towards a specific point, it converges the light rays togther.
How does an image form with your eyes
The light reflects off the object and passes through the pupil, which is controlled by the iris. The cornea and lense focuses the light to the retina, the image is trasmitted with the optic nreve to your brain.
What are the 2 types of photoreceptors and what do they do?
- Rods: react with movement and light
- Cones: react with color and brightness.
