P14 - lenses

Question 1

lens

Answer 1

changes the direction of light passing through it

Question 2

convex lens

Answer 2

makes parallel rays converge to a focus

Question 3

principal focus

Answer 3

point where parallel rays are focused to

Question 4

use of lenses

Answer 4

magnifying glass
in a camera to form a clear image of distant objects

Question 5

concave lens

Answer 5

makes parallel rays diverge (spread out)

Question 6

focal point

Answer 6

where rays come from

Question 7

focal length

Answer 7

distance from centre of lens to focal point

Question 8

ray diagrams

Answer 8

show formation of images by these lenses

Question 9

convex lens: forms a real object when

Answer 9

-object is further away than focal point

Question 10

to form a real object with a convex lens and if object is moved nearer to principle focus =

Answer 10

move screen further away from lens

Question 11

convex lens forms a virtual image when

Answer 11

object is nearer to lens than principle focus

Question 12

nearer the object is too the lens

Answer 12

the larger the object

Question 13

magnification formula

Answer 13

I = AM

Question 14

if image is bigger than the object

Answer 14

magnification >1

Question 15

if image is smaller than the object

Answer 15

magnification <1

Question 16

position and nature of image formed depends on

Answer 16

• focal length
• distance from object to lens

Question 17

ray diagrams are drawn to

Answer 17

• find position and nature of image formed by a lens

Question 18

principle axis of lens

Answer 18

straight line that passes along the normal at the centre of each lens surface

Question 19

when an object is placed between a convex + principle focus =

Answer 19

image is virtual
-upright
-magnified
-same side of lens as the object

Question 20

camera

Answer 20

-convex lens used to produce a real image

Question 21

camera - distant object

Answer 21

• distance from lens to film must be equal to focal length

Question 22

virtual image by convex lens

Answer 22

between lens and principle focus
-image seen only through looking through lens
- eg magnifying glass

Question 23

virtual image by concave lens properties

Answer 23

• virtual
  -upright
  -smaller than object

Question 24

all lenses have a principle focus which will

Answer 24

be on both sides of lens
- equal lengths from centre

Question 25

principle focus always sits on

Answer 25

axis

Question 26

shorter focal length

Answer 26

more powerful lens is

Question 27

to make a lens more powerful =

Answer 27

-more curved
- diff material

Question 28

real image - light rays

Answer 28

come together to form an image

Question 29

virtual image - light rays

Answer 29

don’t come together where image is

Question 30

convex lens - more than 2f = image that is

Answer 30

real
- inverted
diminshed

Question 31

diminshed

Answer 31

smaller

Question 32

convex lens - at 2f exactly forms an image that is

Answer 32

• real
  -inverted
• ## same size

Question 33

convex lens - between 2f and f forms an image that is

Answer 33

• real
• inverted
• larger

Question 34

convex lens - between f and lens

Answer 34

• virtual
  -upright
  -larger