One barn is equal to

Options

A. `10^(-30)m^(2)`
B. `10^(28)m^(2)`
C. `10^(-28)m^(2)`
D. `10^(30)m^(2)`

Explanation

To determine the value of one barn in square meters, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Definition of a Barn**:
A barn is a unit of area commonly used in nuclear physics to describe the cross-sectional area of atomic nuclei.

2. **Convert Barn to Fermi**:
It is given that 1 barn is equal to 100 Fermi square meters. This means:
\[ 1 \text{ barn} = 100 \, \text{Fermi}^2 \]

3. **Convert Fermi to Meters**:
We know that 1 Fermi is equal to \(10^{-15}\) meters. Therefore, we can express 1 Fermi squared in meters:
\[ 1 \text{ Fermi}^2 = (10^{-15} \text{ m})^2 = 10^{-30} \text{ m}^2 \]

4. **Calculate the Area in Square Meters**:
Now, substituting the value of Fermi squared into the equation for barns:
\[ 1 \text{ barn} = 100 \times 10^{-30} \text{ m}^2 \]

5. **Simplify the Expression**:
We can simplify this further:
\[ 1 \text{ barn} = 10^{2} \times 10^{-30} \text{ m}^2 = 10^{-28} \text{ m}^2 \]

6. **Final Result**:
Thus, we conclude that:
\[ 1 \text{ barn} = 10^{-28} \text{ m}^2 \]

### Answer:
The correct answer is \(10^{-28} \text{ m}^2\).

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