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Physics 2 - Waves And The Electromagnetic Spectrum > Lenses > Flashcards

Flashcards in Lenses Deck (20):
1

what does a converging lens look like (convex)

bulges outwards

2

what does a diverging lens look like (concave)

caves inwards

3

what does a converging lens do

causes rays of light parallel to the axis to converge at the principle focus (brought together)

4

what does a diverging lens do

causes parallel rays of light parallel to the axis to diverge (spread out)

5

what is the focal length

distance from center of lens to the principle focus

6

what is a real image

where the light coming from an object comes together to form an image on the screen

7

what is a virtual image

when rays are diverging so the light from the object appears to be coming from a completely different place

8

what type of image does a magnifying glass show

- a magnifying glass shows a virtual image
- because the point at which the object seems to have been created isnt actually the point in which the light rays meet

9

what type of image does an eye form

- a real image
- because of the image formed on the retina

10

what is the axis of a lens

the line going through the middle of the lens

11

what is the principle focus of a converging lens

where the rays hitting the lens parallel to the axis all meet

12

what is the principle focus of a diverging lens

- the point where rays hitting the lens parallel to the axis appear to all come from
- you can trace them back until they all appear to meet up at a point behind the lense

13

how do light rays act when going through a lens in general

- when they enter the lens, they bend towards the normal due to the change in density (going into a more dense area)
- but when they leave the lens from the other side, they refract away from the normal due to the change in density (going into a less dense area)

14

when are images formed

at points when all the light rays coming form something seem to come together at one point

15

why can a real image be captured on screen

because the light rays actually meet at the place the image seems to be

16

why cant a virtual image be captured on a screen

because the light rays dont actually come together at the point the image seems to be

17

what is the focal length related to and what does it mean

- the power of the lens
- it means that the more powerful the lens
- the more strongly it converges the rays of light
- so the shorter the focal point is from the center of the lense

18

what are the powers in a converging and diverging lense

- the power in a converging lens is positive
- the power in a diverging lens is negative

19

what are the two ways in which you can make a more powerful lens

- by increasing the curvature of the lens or making it with more strongly curved surfaces
- or by using materials that are better at focusing light than others

20

what is the effect of a more powerful lens being able to be created by changing the material in which it ia made from

it means that a more powerful lens can be created that is thinner simply by changing the material it is made from