Measuring, Estimating and Units

Hong Kong

Stage 1 - Stage 3

A light year is defined as the distance that light can travel in one year. It is measured to be $9460730000000000$9460730000000000 metres.

a

Write this using scientific notation.

b

How many kilometres is this? Write this using scientific notation.

c

How many centimetres is this? Write this using scientific notation.

Easy

Approx 4 minutes

Light can travel at a speed of $300000000$300000000 m/s.

A micrometre (**µm**) is defined as being a millionth of a metre. This means that $1$1 µm is $0.000001$0.000001 m.

The size of a fog, mist or cloud water droplet is approximately $10$10 µm. How many would fit in a $9$9 cm sample?

Round your answer to the nearest whole unit.

A nanometre (**nm**) is defined as being a billionth of a metre. This means that $1$1 nm is 0.000000001 m.

The germ has an approximate size of $1000$1000 nm. How many would fit in a $9$9 cm sample?

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