Out of the following, which frequency is not clearly audible to the human ear?

Options

A. 30 Hz
B. 30,000 Hz
C. 300 Hz
D. 3000 Hz

Answer

To determine which frequency is not clearly audible to the human ear, we need to understand the range of audible frequencies. The human ear can typically hear sounds in the frequency range of 20 Hz to 20 kHz (20,000 Hz). Any frequency outside this range is considered not audible.

### Step-by-Step Solution:

1. **Identify the Range of Audible Frequencies**:
- The human ear can hear frequencies from 20 Hz to 20,000 Hz (20 kHz).

2. **List the Given Frequencies**:
- We need to evaluate the following frequencies (as per the context of the question):
- 30 Hz
- 30,000 Hz
- 300 Hz
- 3,000 Hz

3. **Evaluate Each Frequency Against the Audible Range**:
- **30 Hz**: This is within the range of 20 Hz to 20 kHz, so it is audible.
- **30,000 Hz**: This is above 20 kHz, so it is not audible to the human ear.
- **300 Hz**: This is within the range of 20 Hz to 20 kHz, so it is audible.
- **3,000 Hz**: This is also within the range of 20 Hz to 20 kHz, so it is audible.

4. **Conclusion**:
- The only frequency that is not clearly audible to the human ear from the given options is **30,000 Hz**.

### Final Answer:
- **30,000 Hz** is the frequency that is not clearly audible to the human ear.