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AustraliaVIC
VCE 12 General 2023

1.06 Log scales

Worksheet
Log scales
1

Using a CAS calculator, find \log_{10} 3828.3 correct to two significant figures.

2

Using a CAS calculator, find x if \log_{10} x = 0.6. Round your answer to two significant figures.

3

The number line below has a \log_{10} scale. Plot the number 100 on the scale below:

-5-4-3-2-1012345
4

Evaluate \log_{10}40. Round your answer to two decimal places.

5

In order to estimate \log_{10}90 without a calculator:

a

Find \log_{10}10.

b

Find \log_{10}100.

c

Hence, which two integers does \log_{10}90 lie between?

6

The logarithm of which number is equal to zero?

7

Solve \log_{10}x = 3.2 for x. Round your answer to two decimal places.

8

Each number line below has a \log_{10} scale. For each number line, determine the value of the point plotted on the line. Round your answers to two significant figures.

a
-5-4-3-2-1012345
b
-5-4-3-2-1012345
9

The data in the table shows the population of 10 countries:

Using a spreadsheet on your CAS calculator calculate the \log_{10} of the population for each country.

Write the results in the table correct to three significant figures.

\text{Country}\text{Population}\text{log}_{10}\text{ Population}
\text{Iran}80\,530\,288
\text{Poland}38\,577\,192
\text{Nepal}29\,032\,238
\text{Senegal}15\,840\,344
\text{Paraguay}6\,771\,929
\text{Georgia}3\,975\,869
\text{Honduras}8\,251\,664
\text{Bhutan}788\,839
\text{Malaysia}30\,974\,279
\text{Denmark}5\,702\,131
10

The data in the table shows the area (in square kilometres) of 10 countries:

Using a spreadsheet on your CAS calculator calculate the \log_{10} of the area for each country.

Write your results in the table correct to three significant figures.

\text{Country}\text{Area}\\ \left(\text{km}^2\right)\text{log}_{10}\text{ Area}
\text{Egypt}1\,001\,450
\text{United Kingdom}244\,820
\text{Mozambique}801\,590
\text{Cambodia}181\,040
\text{Sierra Leone}71\,740
\text{Panama}78\,200
\text{Montenegro}14\,026
\text{Croatia}56\,542
\text{Malaysia}329\,750
\text{Lebanon}10\,400
11

The histogram below shows the weights (in kilograms) of 26 zoo animals plotted on a log scale:

a

A monkey has a weight of 45.8\text{ kg}. What is the \log_{10} of 45.8 correct to two significant figures?

b

What weight (in \text{kg}) does the number - 2 represent on the log weights scale?

c

How many animals have a weight of at least 1000\text{ kg}?

d

What percentage of animals have a weight less than 0.1 \text{ kg}? Round your answer to two significant figures.

e

How many animals have a weight of at least 0.1\text{ kg} but less than 100\text{ kg}?

12

The histogram below shows the income (in dollars) of 24 employees plotted on a log scale:

a

A employee has an income of \$46\,974. What is the \log_{10} of 46\,974 correct to two significant figures?

b

What income does the number 5 represent on the log-income scale?

c

How many people have an income of at least \$10\,000?

d

What percentage of people have an income less than \$100\,000?

e

How many people have an income of at least \$10\,000 but less than \$10\,000\,000?

13

A financial planner has clients with a large range of annual incomes. To manage the data more easily, the income (in dollars) of each client is first converted to a \log_{10} scale.

a

What income would result in 4.9 on a \log_{10} scale?

b

What range of incomes corresponds to a range of 5 to 6 on the \log_{10} scale?

14

The table below lists the oil production in barrels per day for 20 countries:

\text{Country}\text{Oil Production}\\ \text{(barrels per day)}\text{log}_{10}\text{ Oil Production}
\text{Saudi Arabia}10\,625\,000
\text{China}3\,938\,000
\text{Norway}1\,763\,000
\text{India}736\,000
\text{Ecuador}555\,000
\text{Thailand}265\,000
\text{Brunei}113\,000
\text{Uzbekistan}85\,000
\text{France}61\,000
\text{Peru}39\,000
\text{Albania}21\,000
\text{Croatia}18\,000
\text{Belgium}13\,000
\text{Finland}13\,700
\text{Portugal}7100
\text{Bangladesh}4800
\text{Japan}4000
\text{Lativia}1150
\text{Costa Rica}300
\text{Zambia}200
a

Using your CAS calculator, calculate the \log_{10} value of each countries oil production to complete the table.

b

Construct a frequency histogram of log oil production.

15

The lifespans of various animals and insects are shown in the table below:

\text{Animal/Insect}\text{Lifespan (days)}\text{Lifespan in a log}_{10} \text{ scale}
\text{Ant}20
\text{African elephant}25\,5004.41
\text{Bowhead whale}71\,400
\text{Bumblebee}211.32
\text{Chicken}29203.47
\text{Dog}5110
\text{Emperor penguin}85003.93
\text{Fly}18
\text{Giraffe}10\,120
\text{Hamster}7802.89
\text{Ladybug}365
\text{Little penguin}21903.34
\text{Monkey}7300
\text{Shark}10\,9804.04
a

Convert the lifespans to a \log_{10} scale to complete the table, rounding each value to two decimal places. Some values have already been filled in.

b

Create a histogram to represent this data, on a \log_{10} scale.

16

The histogram has been plotted on a \log_{10} scale:

a

What is the total frequency of scores between 1 and 100?

b

What is the total frequency of scores larger than 0.1?

c

What is the total frequency of scores smaller than 10?

17

The given histogram shows the area (in square kilometres) for 12 countries, plotted using a log scale:

How many countries have an area of between 10\,000\text{ km}^2 and 100\,000\text{ km}^2?

18

The histogram shows the masses (in grams) of a group of insects and animals, plotted on a \log_{10} scale:

a

How many animals and insects are included in the data altogether?

b

A caterpillar has a mass of 3 grams. What value does this take on a \log_{10} scale? Round your answer to two decimal places.

c

Which interval on the histogram would include a cat that has a mass of 4.5\text{ kg}?

d

From the data in the histogram, how many of the animals or insects had a mass that was over 100 grams?

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U3.AoS1.3

logarithmic (base 10) scales, and their purpose and application

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