(a) (i)
By using a ruler the final diagram is more likely to be accurate than if drawn freehand. When adding arrows to the lines that represent rays of light make sure that they go in the correct direction and that there are no contradictory arrows. Like the object, the image should always touch the principal axis.
(ii) The image is on the same side of the lens as the object.
This answer is specific. Statements such as ‘in front of the lens’ or ‘behind the lens’ are ambiguous as both statements could refer to either side. Answers such as ‘dashed lines have been used’ do not tell us anything about the image and would not get the mark.
(iii) magnification = image height/object height = 4/2 = 2cm
It may be difficult to be totally accurate in drawing a ray diagram so a tolerance will be allowed in the magnification value. In this case an answer between 1.8 and 2.2 may be acceptable.
(b) The image changes from being virtual and upright to being real and inverted. 3
Two changes have been given; each is worth a mark. The image is still magnified, so this is not a change and therefore should not be mentioned. In order to get this answer you may need to draw another ray diagram. But this time it can just be a quick sketch, as no marks are allocated for producing one.
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