Question 18M.3.SL.TZ1.8
| Date | May 2018 | Marks available | [Maximum mark: 10] | Reference code | 18M.3.SL.TZ1.8 |
| Level | SL | Paper | 3 | Time zone | TZ1 |
| Command term | Calculate, Determine, Discuss, Identify | Question number | 8 | Adapted from | N/A |
A converging (convex) lens forms an image of an object on a screen.
Identify whether the image is real or virtual.
[1]
image is real «as projected on a screen»
[1 mark]
The lens is 18 cm from the screen and the image is 0.40 times smaller than the object. Calculate the power of the lens, in cm–1.
[3]
«»
u = 45
OR
f = 13 «cm»
P = = «» = 0.078 «cm–1»
Accept answer 7.7«D».
[3 marks]
Light passing through this lens is subject to chromatic aberration. Discuss the effect that chromatic aberration has on the image formed on the screen.
[3]
refractive index depends on wavelength
light of different wavelengths have different focal points / refract differently
there will be coloured fringes around the image / image will be blurred
[3 marks]
A system consisting of a converging lens of focal length F1 (lens 1) and a diverging lens (lens 2) are used to obtain the image of an object as shown on the scaled diagram. The focal length of lens 1 (F1) is 30 cm.
Determine, using the ray diagram, the focal length of the diverging lens.
[3]
any 2 correct rays to find image from lens 1
ray to locate F2
focal length = «–»70 «cm»
Accept values in the range: 65 cm to 75 cm.
Accept correct MP3 from accepted range also if working is incorrect or unclear, award [1].
[3 marks]