Topic 6c- Lenses and ray diagrams

Question 1

What is the distance from the principle lens to the focus called?

Answer 1

the focal length

Question 2

what is the line passing through the middle of the lens called

Answer 2

axis

Question 3

what are the images called on either side of the lens

Answer 3

the image on the left (going through the lens) is the virtual image
the image created on the right (the other side of the lens) is the real image remember the Rs go together → real and right

Question 4

convex lens symbol

Answer 4

the arrows pointing outwards

Question 5

concave lens symbol

Answer 5

the arrows pointing inwards

Question 6

steps to draw ray diagram for a convex lens when image is behind F

Answer 6

1. draw horizontal ray from top of the object to the lens
2. from this pont on the lens, draw lines through the principal focus
3. draw a line from the top of the object to the centre of the lens
4. carry this line on to the bottom of the lens
5. the image is formed where these two lines cross

Question 7

steps to draw ray diagram for concave lens

Answer 7

1. draw ray from the top of the object to the centre of the lens
2. draw horizontal line from the top of the object to the lens
3. draw a line from the principle focus on the left of the lens to where the horizontal line meets the lens
4. draw the image where the real and virtual rays from the object meet

Question 8

where is the virtual image produced in a concave lens diagram?

Answer 8

on the left

Question 9

what happens to a ray diagram if the lens is convex and the image is infront of F

Answer 9

THIS IS A MAGNIFYING GLASS
Do the same starting steps as before:

1. draw horizontal ray from top of the object to the lens
2. from this pont on the lens, draw lines through the principal focus on the right
3. draw a line from the top of the object to the centre of the lens
4. continue this line down
5. now extend these lines to the left side of the lens as the lines will never meet on the right
6. now draw the image here

Question 10

what type of lens do magnifying glasses use?

Answer 10

convex