The smallest and largest units of length are

Options

A. Millimeter Centimeter
B. Fermi and Parsec
C. Milimeter and Kilometer
D. Milimeter and Light Year

Answer

To determine the smallest and largest units of length, we can follow these steps:

### Step 1: Identify common units of length
We start by identifying some common units of length. Common units include millimeters (mm), centimeters (cm), meters (m), kilometers (km), and larger astronomical units like light-years and parsecs.

### Step 2: Convert smaller units to meters
We will convert the smaller units into meters to compare their sizes:
- **Millimeter**:
\[ 1 \text{ mm} = 10^{-3} \text{ m} \]
- **Centimeter**:
\[ 1 \text{ cm} = 10^{-2} \text{ m} \]
- **Fermi (fm)**:
\[ 1 \text{ fm} = 10^{-15} \text{ m} \]

### Step 3: Identify the smallest unit
From the conversions, we can see that:
- 1 fermi (10^{-15} m) is smaller than both millimeter (10^{-3} m) and centimeter (10^{-2} m).
Thus, the smallest unit of length is **Fermi**.

### Step 4: Convert larger units to meters
Next, we will consider larger units:
- **Light-year**:
\[ 1 \text{ light-year} \approx 9.461 \times 10^{15} \text{ m} \]
- **Parsec**:
\[ 1 \text{ parsec} \approx 3.086 \times 10^{16} \text{ m} \]

### Step 5: Identify the largest unit
From the conversions, we can see that:
- 1 parsec (approximately \(3.086 \times 10^{16} \text{ m}\)) is larger than 1 light-year (approximately \(9.461 \times 10^{15} \text{ m}\)).
Thus, the largest unit of length is **Parsec**.

### Conclusion
The smallest unit of length is **Fermi** (10^{-15} m) and the largest unit of length is **Parsec** (approximately \(3.086 \times 10^{16} \text{ m}\)).

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