What happens to a digital signal sent using electromagnetic waves as it travels farther from its source? A. The signal becomes weaker and more difficult to detect B. The signal slows down and becomes distorted C. The signal needs to be amplified before it can be detected D. The digital signal changes to an analog signal.
The Correct Answer and Explanation is:
Correct Answer: A. The signal becomes weaker and more difficult to detect
Explanation
When a digital signal is transmitted using electromagnetic waves—such as in radio, television, or wireless internet—it travels through space and gradually weakens the farther it moves from its source. This phenomenon is due to signal attenuation, which is the reduction in signal strength over distance.
As electromagnetic waves radiate outward from an antenna, they spread in all directions. This causes the energy of the signal to be dispersed over a larger area, making it less concentrated and, therefore, weaker. This is similar to how the brightness of a flashlight fades as you move farther away from it.
Additionally, the signal can encounter obstacles such as buildings, trees, and atmospheric interference. These obstacles can absorb or reflect parts of the wave, further reducing its strength and potentially distorting the information being carried. However, the digital signal itself does not change into an analog signal, nor does it inherently slow down—the speed of electromagnetic waves remains constant in a given medium (typically the speed of light in air or vacuum).
As the signal becomes weaker, it becomes more difficult for a receiver (like a smartphone or radio) to accurately interpret the digital 1s and 0s. At some point, the signal-to-noise ratio (SNR) becomes too low, and the receiver may no longer distinguish the original message from background noise. This is why distant signals often require amplification or the use of repeaters to boost their strength along the way.
In summary, as a digital signal transmitted via electromagnetic waves travels farther from its source, it becomes weaker and more difficult to detect, making option A the correct answer. Understanding this principle is essential in fields like telecommunications, satellite broadcasting, and wireless networking.
