Lenses And Images Flashcards
How do lenses form images?
By refracting light and changing its direction.
What is a converging lens?
It’s convex (bulges outwards)
And causes parallel rays of light to converge at the principal focus
What does converge mean?
Move together
What is a diverging lens?
It’s concave (caves inwards) and causes parallel rays of light to diverge
What does diverge mean?
Spread out
What is the axis of a lens?
The line passing through the middle of the lens
What is the principle focus its converging lens?
Where rays hitting the lens parallel to the axis all meet
What is the principle focus of s diverging lens?
The point where all rays hitting the lens parallel to the axis appear to all come from
What is the focal length?
The distance from the centre of the lens to the principal focus
What is a real image?
Where light from an object comes together to form an image on a ‘screen’ (like the retina)
What is virtual image?
When the rays are diverging so the light from the object appears to be coming from a different place
Can’t be projected
What three things do you need to say to describe an image?
How big it is compared to the object
Whether it’s upright or inverted
Whether it’s real or virtual
