STATEMENT-1 Number of significant figures in 0.007 s one and that in 0.700 is true
STATEMENT 2 : All zeros in a number are not significant
STATEMENT 3: Length of a rod is measured 100 m .Number significant figures in this measurement 1

Options

A. TFT
B. FFT
C. TFF
D. FTT

Answer

To analyze the statements regarding significant figures, we will evaluate each statement one by one.

### Step 1: Evaluate Statement 1
**Statement 1:** The number of significant figures in 0.007 s is 1, and that in 0.700 is 3.

- **Analysis of 0.007 s:**
- The leading zeros (0.00) are not counted as significant figures.
- The only significant figure is the '7'.
- Therefore, 0.007 has **1 significant figure**.

- **Analysis of 0.700:**
- The '7' is a significant figure.
- The two trailing zeros after the decimal point (00) are also significant because they indicate precision.
- Therefore, 0.700 has **3 significant figures**.

**Conclusion for Statement 1:** This statement is **true**.

### Step 2: Evaluate Statement 2
**Statement 2:** All zeros in a number are not significant.

- **Analysis:**
- This statement is misleading. While leading zeros (those before the first non-zero digit) are not significant, trailing zeros (those after the decimal point and after a non-zero digit) are significant.
- For example, in the number 0.700, the zeros are significant.

**Conclusion for Statement 2:** This statement is **false**.

### Step 3: Evaluate Statement 3
**Statement 3:** The length of a rod is measured as 100 m. The number of significant figures in this measurement is 1.

- **Analysis:**
- The number 100 can be ambiguous regarding significant figures. However, if it is written as 100 m without a decimal point, it typically indicates that it has 1 significant figure.
- However, in scientific contexts, if the measurement is precise, it is often interpreted as having 3 significant figures (1, 0, and 0).

**Conclusion for Statement 3:** This statement is **false**.

### Final Summary of Statements
- **Statement 1:** True
- **Statement 2:** False
- **Statement 3:** False