Review on Summative Test #1

Avery conducted an experiment to measure the height of a plant. She took several measurements over a week. Accuracy is

• Measurements that are close together

• Measurements that are close to the true value

• How close measurements are to the true value

• How close together measurements are to each other

Answer explanation

Accuracy refers to how close measurements are to the true value. The correct choice highlights this definition, distinguishing it from precision, which relates to the closeness of measurements to each other.

How many sig figs are in 0.0045670?

• 8

• 4

• 5

• 7

Answer explanation

In 0.0045670, the leading zeros are not significant. The digits 4, 5, 6, 7, and the trailing zero are significant, totaling 5 significant figures.

How many significant figures in 20.3400

• 4

• 6

• 5

• 2

Answer explanation

The number 20.3400 has 6 significant figures. All non-zero digits are significant, and zeros between significant digits and trailing zeros in the decimal portion are also counted.

The statement “Precision is independent of accuracy. You can be very precise but inaccurate. You can also be accurate but imprecise.” Is:

• True

• False

• Maybe

• Never true

Answer explanation

The statement is true because precision refers to the consistency of measurements, while accuracy refers to how close a measurement is to the true value. You can have precise measurements that are not accurate, and vice versa.

What is 0.658 rounded to 1 significant figure?

• 0

• 0.66

• 0.7

• 0.658

Answer explanation

To round 0.658 to 1 significant figure, we look at the first digit (6) and the next digit (5). Since 5 is 5 or more, we round up, making it 0.7.

Round off 509.96 to 4 significant figures

• 509.9

• 509.0

• 510.0

• 510

Answer explanation

To round 509.96 to 4 significant figures, we look at the first four digits: 5099. The next digit (6) rounds the last digit (9) up, resulting in 5100. Thus, the correct answer is 510.0.

What is 78.5 rounded to one significant figure?

• 79

• 78.5

• 70

• 80

Answer explanation

To round 78.5 to one significant figure, we look at the first digit (7) and the next digit (8). Since 8 is 5 or more, we round up, resulting in 80. Thus, the correct answer is 80.

The diameter of a carbon atom is 0.000 000 000 154 m. What is this number expressed in scientific notation?

• 1.54 x 10¹² m

• 1.54 x 10^-12 m

• 1.54 x 10¹⁰ m

• 1.54 x 10^-10 m

Answer explanation

To express 0.000 000 000 154 m in scientific notation, we move the decimal point 10 places to the right, resulting in 1.54. Thus, it becomes 1.54 x 10^-10 m, making the correct answer 1.54 x 10^-10 m.

The expression of 5008 km in scientific notation is ____.

• 5.008 x 10³ km

• 50.08 X 10^-4 km

• 5.008 x 10^-3 km

• 5.008 x 10⁴ km

Answer explanation

To express 5008 km in scientific notation, we move the decimal point three places to the left, resulting in 5.008. This gives us 5.008 x 10^3 km, which is the correct choice.

What is the measurement 111.009 mm rounded off to four significant digits?

• 111 mm

• 111.0 mm

• 111.01 mm

• 110 mm

Answer explanation

To round 111.009 mm to four significant digits, we consider the first four digits: 1110. The next digit (9) indicates we round up, resulting in 111.0 mm. Thus, the correct answer is 111.0 mm.