Chapter 5, Problem 25A

(a)

Interpretation Introduction

Interpretation: The number of significant figures needs to be indicated in the given statement relating unit inch to cm.

Concept Introduction: The significant figures are each digit of a number which is used to express that number to the required accuracy starting from the first non-zero digit in the number.

Answer to Problem 25A

One inch equivalent to 2.54 cm has unlimited number of significant figures.

Explanation of Solution

From definitions, exact numbers can also arise. For example, $1\text{inch}=2.54\text{cm}$ . So, its significant figures are infinite. Thus, in statement $1\text{inch}=2.54\text{cm}$ , when it used in computation, neither 2.54 nor 1 can limit the number of significant figures.

(b)

Interpretation Introduction

Interpretation: The number of significant figures needs to be indicated in the given statement indicating 24 homework problems.

Concept Introduction: The significant figures are each digit of a number which is used to express that number to the required accuracy starting from the first non-zero digit in the number.

Answer to Problem 25A

The number is exact so, it has unlimited number of significant figures.

Explanation of Solution

Exact numbers can also arise from definitions. The number given in this statement is exact. According to this question, 24 problems are given for solving. Thus, these numbers have an unlimited number of significant figures.

(c)

Interpretation Introduction

Interpretation: The number of significant figures needs to be indicated in the given statement with $\$249.75$ needs to be determined.

Concept Introduction: The significant figures are each digit of a number which is used to express that number to the required accuracy starting from the first non-zero digit in the number.

Answer to Problem 25A

Significant figures in $\$249.75$ is $5$ .

Explanation of Solution

The given number is $\$249.75$ , it contains 5 non-zero digits. Since, all non-zero digits are significant thus, the number of significant figures is 5.

(d)

Interpretation Introduction

Interpretation: The number of significant figures needs to be indicated in the given statement with 2500 mi needs to be determined.

Concept Introduction: The significant figures are each digit of a number which is used to express that number to the required accuracy starting from the first non-zero digit in the number.

Answer to Problem 25A

Significant figure of $2500\text{mi}$ is 2.

Explanation of Solution

The given number is 2500, there are 2 non-zeros and 2 zero digits. Since, all non-zero digits are significant and trailing zeros after decimal are significant thus, there are only 2 significant figures that is 2 and 5.