# 3.1.1 Try some yourself

## Activity 33

Express each of the following numbers in scientific notation.

(a) Light travels 9460 700 000 000 km in a year.

(b) The average distance from the centre of the Earth to the centre of the Moon is 384 400 km.

(c) Saturn is 1427 000 000 km from the Sun.

(d) The mass of the Earth is 5976 000 000 000 000 000 000 000 kg.

(e) The Mediterranean Sea has an area of 2504 000 km

^{2}.(f) Annapurna 1 is 8075 m high.

(g) The diameter of the Sun is 1392 000 km. Use metres in your answer.

### Answer

(a) Light travels at 9.4607 × 10

^{12}km in a year.(b) The distance from the centre of the Earth to the centre of the Moon is 3.844 × 10

^{5}km.(c) Saturn is 1.427 × 10

^{9}km from the Sun.(d) The mass of the Earth is 5.976 × 10

^{24}kg.(e) The Mediterranean Sea has an area of 2.504 × 10

^{6}km^{2}.(f) Annapurna 1 is 8.075 × 10

^{3}m high.(g) 1392 000 km is 1392 000 000 m (multiplying by 1000). In scientific notation this is

1.392 × 10

^{9}m.(Alternatively: 1392 000 km is 1.392 × 10

^{6}km = 1.392 × 10^{6}× 10^{3}m = 1.392 × 10^{9}m.)

## Activity 34

The following numbers are given in scientific notation. Write each out as a single decimal number.

(a) Ben Nevis is 1.343 × 10

^{3}m high.(b) Mercury is 5.8 × 10

^{7}km from the Sun.(c) The distance from the Earth to the nearest star is about 4.3 × 10

^{13}km.(d) The Earth has a circumference of 4.0078 × 10

^{4}km at the equator.(e) The span of the Golden Gate Bridge is 1.28 × 10

^{3}m.(f) The Arctic Ocean has an area of 1.3986 × 10

^{7}km^{2}.

### Answer

(a) Ben Nevis is 1343 m high.

(b) Mercury is 58 000 000 km from the Sun.

(c) The distance from the Earth to the nearest star is about 43 000 000 000 000 km.

(d) The Earth has a circumference of 40 078 km at the equator.

(e) The span of the Golden Gate Bridge is 1280 m.

(f) The Arctic Ocean has an area of 13 986 000 km

^{2}.

## Activity 35

Express each of the following in scientific notation.

(a) 0.53

(b) 0.0075

(c) 0.000 004

(d) 0.000 020 01

### Answer

(a) 0.53 = 5.3 × 10

^{−1}(b) 0.0075 = 7.5 × 10

^{−3}(c) 0.000 004 = 4 × 10

^{−6}(d) 0.000 020 01 = 2.001 × 10

^{−5}

## Activity 36

Express each of the following in conventional decimal notation.

(a) 2.03 × 10

^{−4}(b) 1.4 × 10

^{−3}(c) 5.67 × 10

^{−5}

### Answer

(a) 2.03 × 10

^{−4}= 0.000 203(b) 1.4 × 10

^{−3}= 0.0014(c) 5.67 × 10

^{−5}= 0.000 0567