how lenses work

Question 1

convex lens (converging)

Answer 1

reflect parallel ray of light, inwards to a single point

Question 2

principal focus (focal point)

Answer 2

• on both sides, equal distance from the centre
  ^ this means that they are symmetrical; work both ways.

Question 3

concave lens (diverging)

Answer 3

reflect parallel rays outwards (disperse the light)

Question 4

principal focus (focal point)

Answer 4

• on both sides, equal distance from the center
  ^ this means that they are symmetrical; work both ways.

Question 5

focal length

Answer 5

distance between center of the length and focal point.
- shorter = stronger lens (refracts stronger)

Question 5

to make a lens stronger:

Answer 5

• make it more curved
• use a material that naturally refracts light more

Question 6

how are images formed?

Answer 6

images are formed at points where all the light rays from a particular point on an object appear to come together.

Question 7

real image

Answer 7

when the light rays ACTUALLY come together to form the image.

Question 8

virtual image

Answer 8

formed when the light rays don’t come together where the image appears to be.
- e.g. a mirror (solid; no light rays behind it)

Question 9

u—–

Answer 9

upright

Question 10

in—-

Answer 10

inverted

Question 11

bi—-

Answer 11

bigger

Question 12

s—–

Answer 12

smaller