Write two factors justifying the need of modulation for transmission of a signal.

Explanation

### Step-by-Step Solution:

1. **Understanding Modulation**: Modulation is the process of varying one or more properties of a periodic waveform (the carrier signal) with the information signal that typically contains messages.

2. **Need for Modulation**:
- **Factor 1: Antenna Size**: Low-frequency signals require large antennas for effective transmission. Specifically, the height of the antenna must be approximately 1/4 of the wavelength of the signal. For low-frequency signals (like those in the AM radio range), this can result in antennas that are impractically tall, often requiring heights of 4 to 5 kilometers. Such dimensions are not economical or feasible to construct.
- **Factor 2: Effective Power Radiation**: The effective power radiated by an antenna is inversely proportional to the square of the wavelength. This means that as the wavelength increases (which happens with lower frequencies), the power that can be effectively radiated decreases. Modulation allows for the transmission of signals at higher frequencies, which can be radiated more effectively with smaller antennas.

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