DP Biology (first assessment 2025)

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Question 20N.1B.SL.TZ0.1a

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Date November 2020 Marks available [Maximum mark: 2] Reference code 20N.1B.SL.TZ0.1a
Level SL Paper 1B Time zone TZ0
Command term Calculate Question number a Adapted from N/A
a.
[Maximum mark: 2]
20N.1B.SL.TZ0.1a
(a)

Calculate the magnification of the image, showing your working.

 

. . . . . . . . . . . . . . . . . . . . x

[2]

Markscheme

Calculation: size of bar ÷ 15 μm (1.5 cm ÷ 15 μm or 15 000 μm ÷ 15 μm);

Answer: 1000 x;

First marking point is for division by 15 μm;

Second marking point is for the correct answer; accept 930 and 1070 x.

Examiners report

Most candidates managed to calculate the magnification correctly by dividing their scale bar measurement by the provided scale, others inverted the division or displayed incomprehensible calculations; some calculations were difficult to follow, with no apparent methodology or structure; there were too many unit conversion errors, sometimes because candidates did not use units within their calculation (e.g. measuring in centimetres, but calculating as millimetres); a limited number measured the complete image width but didn't adjust the scale bar proportionally.