P14 - Light Flashcards
What are the two main types of lenses
Convex and concave
What is another name for a convex lens and why?
Converging lens because they cause the light rays to converge (come together)
What is the shape like in a convex lens?
The lens buldges outwards
What does the bulging shape of convex lens cause parallel rays to do?
Causes rays of light to be broight together at the principle focus
What is the shape like in a concave lens?
The lens caves inwards
What does the caving shape of convex lens cause parallel rays to do?
Causes parallel rays of light to diverge (spread out)
All lenses have a principle focus on both sides. True or False?
True
The two principle focuses on both sides are the same distance from the lens. True or false?
True
What is another term for the principle focus?
The focal point
What will the principle focus ALWAYS sit on?
The axis
What is the focal length?
Thr distcance between the centre of the lens and the principle focus
If the shorter the focal length is, the more __________ the lens will be
Powerful
What does it mean when a lens is more powerful?
It refracts light more strongly
How do you make a lens more powerful?
Make the lens more curved
Or use a different material that refracts light more strongly
How is an image formed?
When all the light rays from a particular point on a object, appear to come together
What is a ‘real image’?
Where light rays come together to form an image on a ‘screen’
What is a ‘real image’?
Where light rays come together to form an image on a ‘screen’
What is a virtual image?
Where light rays dont come together, so the light from the object appears to be coming from a different place
What is the most common example of a virtual image?
A mirror
Why is a mirror an example of a virtual image?
You appear to be behind the mirror,
but there is no rays behind the mirror
because its a solid that light cant past through
When you comment on a real image example, what must you say?
Its real
The image is inverted
The image is smaller
When you comment on a virtual image example, what must you say?
Its virtual
The image is upright
The image is smaller
What image does a convex lense always produce?
A virtual image
How to calculate the magnification produced by a lens?
Magnification = image height / object height
