lenses and images

Question 1

what is an object at 2F?

Answer 1

real, inverted and same size

Question 2

what is an object between F and 2F?

Answer 2

real, inverted and bigger

Question 3

what if an object is nearer to F?

Answer 3

it will be a virtual image, right way up, bigger and on the same side

Question 4

what are diverging images?

Answer 4

virtual, the right way up, smaller and on the same side of lens as object

Question 5

what does the converging lens cause?

Answer 5

the convex lens to bulge outwards which causes parallel rays of light to converge (move together) at principal focus

Question 6

what does a diverging lens cause?

Answer 6

the concave to cave inwards which causes parallel rays of light to diverge (spread out)

Question 7

what is the axis of a lens?

Answer 7

a line passing through the middle of lens

Question 8

where is the principal focus of a converging lens?

Answer 8

rays hitting lens parallel to axis all meet

Question 9

where is the principal focus of a diverging lens?

Answer 9

the point where rays hitting lens parallel to axis appear to all come from (trace them back)

Question 10

where is the principal focus on each side of the lens?

Answer 10

the distance from the centre of the lens (focal length)

Question 11

real images

Answer 11

light from object comes together to form an image on the screen (like image on retina)

Question 12

virtual images

Answer 12

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

Question 13

mirror

Answer 13

is a virtual image because the object appears to be behind the mirror

Question 14

magnifying lens

Answer 14

is a virtual image because the image looks bigger that it actually is

Question 15

describing an image?

Answer 15

• how big it is compared to the object?
• upright/inverted?
• real/virtual?