Solution: (a) Most telephone wires are made out of copper, which contracts with drop in temperature and hence breaks in winter if it becomes too tight between the poles. (c) The gaps are
left between the successive rails for making space for their expansion when there is rise in temperature in summers
.
Why are telephone wires loosely fixed on electric poles?
the wires are made of aluminium which has a property of contracting during winter season. so to
avoid breakage of
these wires they are fixed loosely between two poles.
Why electric wires are left sagging?
The lines are often heavily loaded because of increased power consumption, and the conductors, which are generally made of copper or aluminum, expand when heated. That
expansion increases the slack between transmission line structures
, causing them to sag.
Why are power lines not hung tightly?
The reason is
to minimize the tension in the wire
. The wires expand when exposed to intense heat from sun and contract during cold weather. Stretching the wire and connecting to the poles will make the wires loosen up and tear easily. This might lead to an accident.
Why are telephone lines sometimes taut and sometimes loose?
Answer Expert Verified
Telephone wires are made up of Copper. … So, during summer
the rising temperature makes the copper in the wire expand
– so it gets sagged. but, during winter, the scenario is completely reverse and the copper contracts and so the wire becomes tight.
Why do electrical overhead wires hang loosely instead of being stretched tightly?
During transmission of electricity,
heat is being dissipated
. The heat generated by cables is being minimized via high voltage transmission. … So, the cables are loose so that even if contraction should occur, there won’t be much tension which would lead to the damage of the cables.
Why are electric transmission wires stretched tightly when they are laid in winter?
the electric transmission lines are stretched tightly in winter
due to the decrease in temperature where the wires contract
and in summer the situation is opposite . The thermal expansion due to heat loosens and expands the wires..
Why do electric wires sag in summer?
The telephone wires will sag in summer
due to expansions
. While putting up the wires between the pole care is taken care in winter they are kept light so that they may not sag too much. … So telephone wires will sag in summer due to expansion while you do suspect because of because of because of sighing expansion.
What causes sagging of electric wires during summer?
This process is called
thermal expansion
. The same process happens in the electric wire. During summer, the heat makes the molecules move wider apart and hence it sags and during the winter follows the opposite process and gets contacted.
What is the purse like structure hanging on electricity wires?
They’re called
visibility marker balls or marker balls
. You’ll often find them near mountain passes, in the deep valley areas, near major freeway crossings and around airports. They weight about 17 pounds each. The marker balls are placed on power lines to make the conductor crossings visible to aircraft.
Why do electrical wires sag in the summer and hang tight in the winter?
Because the cores of overhead wires are made from copper. Metals expand with heat and contract with cold. The higher temperatures in summer make the copper expand – so the lines get slightly longer. In winter, the reverse happens –
the lines contract and tighten up
.
Why do telephone wires become taut in winter?
Hint: Telephone wires are made up of metals and as we know that metals tend to expand in hot temperatures and shrink in cold temperatures. The wires are usually made up of copper or aluminum.
The wires expand due to thermal expansion
, while in winters they contract and become taut.
Why are the telephone’s cables taut in winter and slacken in summer?
Why do the telephone wires get slackened in summer and get tightened in winter? In summers
due to excessive heat, the temperature of the wire increases and wires expand
.
Do power lines sag more in summer than winter?
Originally Answered: Why do power lines sag more in the summer than in the winter?
They expand from the temperature difference
. While the expansion is not much, over a long distance, such as. between two transmission towers, it is enough to cause a visible sag.
Why do electric wires appear tight on cold days?
Metals expand with heat and contract with cold. The higher temperatures in summer make the copper expand – so the lines get slightly longer. In winter,
the reverse happens
– the lines contract and tighten up.
