The essential condition for demodulation is

Options

A. `v_(c)lt lt RC`
B. `(1)/(v_(c))lt lt RC`
C. `(1)/(v_(c))gt gtRC`
D. `v_(c)gt gtRC`

Explanation

### Step-by-Step Solution:

1. **Understanding Demodulation**:
- Demodulation is the process of extracting the original information signal from a modulated carrier wave. It is essentially the reverse of modulation, where a low-frequency audio signal is superimposed onto a high-frequency carrier wave.

2. **Purpose of Demodulation**:
- The primary goal of demodulation is to retrieve the low-frequency signal (the original information) from the high-frequency carrier wave. This allows the information to be processed or transmitted further.

3. **Essential Condition for Demodulation**:
- For demodulation to occur effectively, there is a specific condition that must be met regarding the relationship between the carrier frequency (νC) and the RC time constant of the circuit used in demodulation.
- The condition states that the carrier frequency (νC) must be much less than the product of resistance (R) and capacitance (C) in the RC circuit used for demodulation.

4. **Mathematical Representation**:
- The condition can be expressed as:
\[ νC \ll R \times C \]
- This implies that the RC product should be greater than or equal to a certain threshold (often taken as 1) for effective demodulation.

5. **Conclusion**:
- Therefore, the essential condition for demodulation is that the product of resistance and capacitance (RC) must be sufficiently large relative to the carrier frequency.