waves - concave lenses

Question 1

concave lens symbol

Answer 1

vertical line with inward facing arrows

Question 2

describe concave lens?

Answer 2

thicker at edges than centre

Question 3

what happens when rays of light hit concave lens?

Answer 3

light rays will spread out (diverge).

Question 4

how do you find concave lens prinicpal focus?

Answer 4

draw dotted lines back from point of diverge until they meet at a point

Question 5

what is concave not focusing the light at? what do they appear to be?

Answer 5

principal focus
appear to be coming from principal focus (not actually)

Question 6

drawing image created by concave lens

Answer 6

• draw ray from object through centre of lens without changing direction
• draw another ray from top of object which passes through lens and then refracted (left). this ray needs to appear to have come from principal focus ( draw dotted lines)
• where lines meet shows position of image

Question 7

properties of image created by concave lens?

Answer 7

diminished (smaller), right way up, virtual (rays don’t actually cross there)