Frequency Range for a Headphone as a Detector

The correct answer is option 'D' which states that the frequency range for a headphone as a detector is 250 Hz to 4 kHz. Let's understand why this is the correct answer.

1. What is a headphone detector?
A headphone detector is a device used to convert electrical signals into sound waves that can be heard through headphones. It is commonly used in various applications such as audio systems, communication devices, and music players.

2. Frequency range of human hearing
The human hearing range typically falls between 20 Hz to 20 kHz. This means that humans can hear sound waves within this frequency range. However, certain frequencies within this range may not be audible to everyone due to factors such as age and hearing ability.

3. Frequency response of headphones
Headphones are designed to reproduce sound across a specific range of frequencies, known as the frequency response. The frequency response of headphones determines the range of frequencies it can effectively reproduce.

4. Choosing the frequency range for a headphone as a detector
In the context of a headphone being used as a detector, it is important to consider the specific frequencies that need to be detected. Different applications may require different frequency ranges to be detected accurately.

- Option 'A' (20 Hz to 20 kHz) includes the entire human hearing range, but it may not be necessary to detect such a wide frequency range in all scenarios. This option covers a broader range than necessary.

- Option 'B' (10 kHz to 1 MHz) and Option 'C' (10 MHz to 1 GHz) cover much higher frequencies than typically required for audio applications. These frequency ranges are more suitable for radio frequency (RF) detection rather than audio detection.

- Option 'D' (250 Hz to 4 kHz) covers a narrower frequency range that is commonly associated with the audible range of human speech and many musical instruments. This range is suitable for detecting and reproducing sound in various audio applications such as speech recognition, music playback, and telecommunication.

Therefore, option 'D' is the correct answer as it provides a reasonable and practical frequency range for a headphone used as a detector in audio applications.