25. The electrical telegraph was the first point-to-point messaging system. This system worked by
sending electrical signals through a wire laid between
two stations. The telegraph system was
eventually replaced by the
telephone system.
Which statement best identifies the primary difference between these two
communication
systems?
A. The telegraph converts mechanical energy to electrical signals; the telephone converts
sound energy to light
waves that are reflected from satellites to receiving stations.
B.
The telegraph converts sound waves to electrical signals that generate a code at the
receiving station;
the telephone converts light waves to electrical signals that generate
sound waves.
C. The telegraph transmits mechanical signals to produce sound waves at the receiving
station; the telephone
produces sound waves that are converted to electrical energy at a
receiving station.
D. The telegraph transmits coded electrical signals that are decoded at a receiving station;
the telephone converts
sound waves to electrical signals that travel through an
electrical
connection.



Answer :

The primary difference between the telegraph and the telephone systems is as follows:

D. The telegraph transmits coded electrical signals that are decoded at a receiving station; the telephone converts sound waves to electrical signals that travel through an electrical connection.

Explanation:
1. Telegraph: It transmits coded electrical signals through a wire to convey messages. The receiving station decodes these signals to interpret the message. It does not involve the transmission of sound waves directly.

2. Telephone: It converts sound waves (produced by the speaker) into electrical signals that travel through a wire or connection to the receiving end. At the receiving station, these electrical signals are converted back into sound waves, allowing for real-time communication through the transmission of sound.

This difference highlights that the telegraph operates based on coded electrical signals for communication, while the telephone operates by converting sound waves into electrical signals and vice versa, enabling voice communication between individuals.