Question

Why are telephone and electrical cables strung out a little loose between the poles?
A. To transfer high voltage
B. To prevent contraction and snapping of the wire during winter
C. To avoid confusion in connecting the wires
D. To avoid congestion over poles

Answer 1

Hint: The electric cables and telephone cables are used to carry the current and signals from the power station and the network station to the different areas in our surroundings. Sometimes we see these cables as strung, sagged or remain tight, and this happens because of temperature change in our atmosphere.

Complete answer:
The materials which cables are made of when exposed to cold the molecules of the cable materials contract and come closer to each other due to cold. This causes them to come close apart. This process is called thermal contraction. The same process happens in the telephone cables or electrical wire.During winter, the cold makes the molecules move close apart and hence it is tight and during the summer follows the opposite process and expands.

While designing the cables, these must be considered. The other examples of the thermal contraction and expansions are bridges constructed along the rivers, railway lines, lid of the glass jar etc. Thus, from the above explanation we can conclude that to avoid contraction and breaking of cables during winter the cables are strung out or a little loose between the poles in our areas.

Hence the correct option is A.

Note: If the cables are laid in summer in a tight way, it gets tighter at the time of winter. If the cables are laid loosely in the winter, then it cannot expand in summer causing it to snap. Resulting the selection of the cable material and the season must be considered while designing them in surroundings.