3a.2 - Refractive Index and Ray Diagrams Flashcards
What is refraction caused by?
Waves changing speed
What way does light bend when it enters a denser medium?
It slows down and bends towards the normal
What happens when light hits a boundary at 90 degrees?
It doesn’t change direction but it slows down
What is refractive index?
It is the ratio of speed of light in a vacuum to speed of light in that medium
What is another name for a converging lens?
Convex
What is another name for a Convex lens?
Converging
What is another name for a diverging lens?
Concave
What is another name for a concave lens?
Diverging
What is a virtual image?
It cannot be projected on to a screen
Where do the rays of light go on a converging lens ray diagram? (2)
- One through the top and through the focal point with an arrow
- One through the centre with an arrow
Where do the rays of light go on a diverging lens ray diagram? (4)
- One from the top of the object, stopping at the centre
- A dotted line from the first focal point to the line then draw the line on
- Draw a line straight through
- Arrows
What type of ray diagram always shows a virtual image?
Diverging
What type of lenses do magnifying glasses use?
Converging
State the magnification formula
Magnification = image height % object height
What is the equation for calculating the power of a lens?
Power = 1
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Focal length
