Question

Aluminium is preferred in overhead power cables because
A. It is a good conductor
B. It acts as an insulator in case of lightning.
C. It prevents accidents
D. It is lighter in weight.

Answer 1

Hint: We know that all metals are good conductors of electricity. Aluminium is a metal. Generally, copper is used in household electrical wires but when it comes to overhead power cables aluminium is preferred because it has better conductivity to weight ratio.

Complete answer:
We know that aluminium is a metal. Metals are generally good conductors of electricity. The conductivity of a metal is the ability to allow electricity to pass through it. Since aluminium is a metal with low resistance and good conductivity it is used in electrical wires. So, option A is correct.
Usually in our household electric wires copper is used. Copper is a good conductor and it conducts electricity better than aluminium. But even when aluminium conducts less well than copper, in the case of overhead power cables aluminium is used because aluminium has comparatively less weight than copper and is also available at a cheap rate. Aluminium wire will be much thicker but it will be lighter compared to copper since the density of aluminium is only one third of that of copper.
The conductivity to weight ratio of aluminium is better than that of copper that is why we prefer aluminium in overhead power connections.

So, answer option D is also correct.

Note:
Remember that aluminium conducts less well when we compare it with copper. But copper is comparatively heavier. The density of aluminium is only one third of the density of copper. So, the light weight of aluminium is the main reason for using aluminium instead of copper in overhead connections.