SI units test with answers for GCSE physics (free PDF download)

Quick answer: SI units are the internationally agreed units for measurement: metre for length, kilogram for mass, second for time, ampere for current and kelvin for temperature. This Physics 9-10 test on SI units has 8 questions worth 20 marks, to do in 45 minutes: SI base units, prefixes and standard form. The mark scheme is on a separate page; free printable PDF.

Also, this test covers SI units, prefixes, standard form, significant figures and the reliability of measurements. Then, show your working, include units and give answers to a sensible number of significant figures. Also, calculators are allowed.

Level: Physics grades 9-10 (GCSE · IGCSE · O Level · Class 9-10) · Curriculum: GCSE WS, IGCSE 1.1

Time: 45 minutes · 8 questions · Total: 20 marks · Calculator allowed

Contents

Question 1 SI base units (2 marks)

In addition, state the SI base unit of mass. (1 mark)
State the name and symbol of the SI unit of electric current. (1 mark)

Question 2 Prefixes (2 marks)

Afterwards, write 3.6 MHz in hertz, in standard form. (1 mark)
Moreover, write 250 µm in metres, in standard form. (1 mark)

Question 3 Standard form (2 marks)

In addition, write 0.000 83 s in standard form. (1 mark)
Also, write 6.02 × 10⁴ as an ordinary number. (1 mark)

Question 4 Significant figures and reading (3 marks)

State the number of significant figures in 0.03080. (1 mark)
Then, round 4.0951 to 3 significant figures. (1 mark)
In addition, record the length of the leaf shown, in cm. (1 mark)

A leaf placed against a ruler.

Question 5 Area of a field (3 marks)

A rectangular field measures 24.5 m by 8.2 m. Then, calculate its area, giving the answer to an appropriate number of significant figures in standard form. (3 marks)

Question 6 Precision and accuracy (3 marks)

Afterwards, the true mass of a stone is 50.0 g. Student X measures 49.9 g, 50.1 g, 50.0 g. Student Y measures 52.1 g, 52.1 g, 52.2 g.

State which student is more accurate. (1 mark)
Moreover, state which student is more precise and give the evidence. (1 mark)
Also, suggest a cause of Student Y’s error. (1 mark)

Question 7 Mean and uncertainty (3 marks)

A ball’s fall is timed four times: 2.31 s, 2.35 s, 2.29 s, 2.33 s. Moreover, calculate the mean time, the uncertainty (half the range) and the percentage uncertainty. (3 marks)

Question 8 Unit conversion (2 marks)

Then, convert 72 km/h to m/s. Show your working. (2 marks)

SI base unit of length? — The metre (m).

SI base unit of mass? — The kilogram (kg).

What does kilo mean? — 10³, or 1000.

What does milli mean? — 10⁻³, or one thousandth.

What does micro (µ) mean? — 10⁻⁶, or one millionth.

Standard form pattern? — a × 10ⁿ with a from 1 up to (not including) 10.

Do leading zeros count as significant figures? — No, they never count.

Define accuracy. — How close a result is to the true value.

Define precision. — How close repeated results are to each other.

Uncertainty from repeats? — Half the range: (largest − smallest) ÷ 2.