State one advantage and one disadvantage of using thicker wire in overhead power line.
Answers
Thinner the wire, more is power consumed.
The power consumed by the wire is nothing but heat loss took place in it.
The heat loss is given by; (I^2 )*R. Where R is resistance of wire element.
Now, R=(resistivity)*length/(area of cross-section) and I=V/R
The thinner a wire, the higher its electrical resistance. This is because the same number of electrons must squeeze through a smaller portal (the wire), and get in each others way in the process, thereby resisting the flow.
Think of a huge crowd of people trying to get down a narrow hall-way at a stadium. In the larger hallways, the crowd is moving just fine, but when they encounter the narrower hallway, they all try to squeeze in, but can't all fit at the same time, leading to resistance in the crowd's movement, so that the movement slows down at in the narrow hallway.
The key point is that the more electrical resistance an object has, the hotter it gets. As the electrons experience resistance bumping into each other and into the atoms of the wire, that bumping action converts forward motion (the electrical current) into random motion (thermal energy). That heat than spreads out beyond the wire. If the thermal energy gets too high, it can even vaporize the wire (that's how fuses work) or even start a fire in nearby materials. In summary, smaller wires have higher resistance and therefore waste more of the electrical energy to heat.