| Date | May 2018 | Marks available | 1 | Reference code | 18M.3.SL.TZ2.8 |
| Level | Standard level | Paper | Paper 3 | Time zone | Time zone 2 |
| Command term | Calculate | Question number | 8 | Adapted from | N/A |
Question
A ray diagram for a converging lens is shown. The object is labelled O and the image is labelled I.
Using the ray diagram,
determine the focal length of the lens.
calculate the linear magnification.
The diagram shows an incomplete ray diagram which consists of a red ray of light and a blue ray of light which are incident on a converging glass lens. In this glass lens the refractive index for blue light is greater than the refractive index for red light.
Using the diagram, outline the phenomenon of chromatic aberration.
Markscheme
constructs ray parallel to principal axis and then to image position
OR
u = 8 cm and v = 24 cm and lens formula
6 «cm»
eg: 
Allow answers in the range of 5.6 to 6.4 cm
[2 marks]
m = «–»3.0
[1 mark]
completes diagram with blue focal point closer to lens
blue light/rays refracted/deviated more
OR
speed of blue light is less than speed of red light
OR
different colors/wavelengths have different focal points/converge at different points
First marking point can be explained in words or seen on diagram
[2 marks]
