Two rods with lengths 12.321cm and 10.3 cm and placed side by side. The difference in their lengths is

Options

A. `2.02 cm`
B. `2.0 cm`
C. `2 cm`
D. `2.025 cm`

Answer

To find the difference in lengths of the two rods, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the lengths of the rods**:
- Length of rod 1 (L1) = 12.321 cm
- Length of rod 2 (L2) = 10.3 cm

2. **Calculate the difference in lengths**:
- Difference (D) = L1 - L2
- Substitute the values:
\[ D = 12.321 \, \text{cm} - 10.3 \, \text{cm} \]

3. **Perform the subtraction**:
- Align the numbers for subtraction:
\[ \begin{array}{r} 12.321 \\ -10.300 \\ \hline \end{array} \]
- Perform the subtraction:
\[ D = 12.321 - 10.300 = 2.021 \, \text{cm} \]

4. **Consider significant figures**:
- The number of significant figures in L1 (12.321 cm) is 5.
- The number of significant figures in L2 (10.3 cm) is 3.
- The result should be reported with the least number of significant figures, which is 3 in this case.

5. **Round the result**:
- Round 2.021 cm to 3 significant figures:
- The rounded value is 2.02 cm.

### Final Answer:
The difference in their lengths is **2.02 cm**.