The diameter of a wire is measured to be 0.0250 `xx` `10^(-4)` m. The number of significant figures in the measurement is

Options

A. five
B. four
C. three
D. nine

Answer

To determine the number of significant figures in the measurement of the diameter of the wire, we will analyze the given number step by step.

### Step 1: Identify the given measurement
The diameter of the wire is given as:
\[ 0.0250 \times 10^{-4} \text{ m} \]

### Step 2: Focus on the significant figures
When determining significant figures, we can ignore the scientific notation (the \(10^{-4}\) part) and focus solely on the decimal number:
\[ 0.0250 \]

### Step 3: Analyze the digits
In the number \(0.0250\):
- The leading zeros (the zeros before the first non-zero digit) are not significant. Therefore, the zeros before '2' (i.e., '0.0') do not count.
- The digits '2' and '5' are significant because they are non-zero digits.
- The trailing zero (the last '0' after '5') is significant because it comes after a decimal point and follows a non-zero digit.

### Step 4: Count the significant figures
Now, we can count the significant figures:
- The digits '2', '5', and the trailing '0' contribute to the significant figures.
- Therefore, the significant figures in \(0.0250\) are: **2, 5, and 0**.

Thus, the total number of significant figures in the measurement \(0.0250\) is **3**.

### Conclusion
The number of significant figures in the measurement of the diameter of the wire is:
\[ \text{3 significant figures} \]