P7 Page 5 Flashcards
0
Q
What is a principal axis?
A
A line that goes through the middle of all lenses.
1
Q
What is a converging lens?
A
A lens that gets fatter towards the middle, it causes rays of light to converge to a focus.
2
Q
What is the focal length?
A
It is the distance from the centre of the lens to the focal point.
3
Q
How is focal length related to the power of a lens?
A
The shorter the focal length, means the stronger the lens converges light.
4
Q
Power(D)=
A
1
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Focal length(m)
5
Q
When are rays considered parallel?
A
When the source is thought to be very far away.
