Two musical notes that have a frequency ratio of 2 : 1 are said to be separated by an octave.
A musical note that is separated by an octave from middle C (256 Hz) has a frequency of _______ .

Options

A. 128 Hz
B. 254 Hz
C. 258 Hz
D. 345 Hz

Answer

To find the frequency of a musical note that is separated by an octave from middle C (256 Hz), we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of Octave**:
- An octave means that the frequency of one note is double that of another note. Therefore, if one note has a frequency \( f \), the note an octave higher will have a frequency of \( 2f \).

2. **Identify the Given Frequency**:
- The frequency of middle C is given as 256 Hz.

3. **Calculate the Frequency of the Note an Octave Lower**:
- To find the frequency of the note that is one octave lower than middle C, we need to divide the frequency of middle C by 2.
- Therefore, the frequency of the note an octave lower is:
\[ f' = \frac{256 \text{ Hz}}{2} \]

4. **Perform the Calculation**:
- Calculating \( f' \):
\[ f' = \frac{256}{2} = 128 \text{ Hz} \]

5. **Conclusion**:
- The frequency of the musical note that is separated by an octave from middle C (256 Hz) is **128 Hz**.

### Final Answer:
The frequency of the musical note that is separated by an octave from middle C (256 Hz) is **128 Hz**.

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