Edexcel IGCSE Physics Standard-form Numbers

Practise Edexcel IGCSE Physics standard-form numbers by multiplying powers of ten in speed, time and distance calculations.

Exam points

Multiply speed and time values written in standard form to show a distance to a power of ten.

[Maximum number: 2]

A star has a circular orbit around the centre of a galaxy.

The speed of light is 3.0 x 10^8 m/s.
One light year is the distance light travels in one year.
Show that one light year is approximately 10^16 m.
[one year = 3.2 x 10^7 s]

Marking points:
- evidence of distance = average speed $\times$ time
- correct evaluation given to at least 2 significant figures

Example:
$\text{distance}=3.0\times10^{8}\times3.2\times10^{7}$ $\text{distance}=9.6\times10^{15}\ \mathrm{m}$

Final answer:
$\text{one light year}\approx10^{16}\ \mathrm{m}$

Accept:
- $9.5\times10^{15}\ \mathrm{m}$

Manual structural note:
- Official 8(b)(ii) is missing as a separate row and must not be merged into this 8(b)(i) answer.

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1B Standard-form numbers question 1