Answer:
Explanation:
The equation that relates voltage, current and resistance is V=RI, and we can calculate this resistance in terms of the resistivity of a material , its length L and cross-section (area) A with:
Putting both equations together we have:
Which will be useful to write as:
since each term on the left will be the same for both situations, thus making the term on the right the same for both situations (which we will call 1 and 2), so we have:
Which we want to write as (since the ratio of the diameter is asked):
Since the areas appear to be that of a circle, we can write them as where r is the radius of that circle, and d the diameter. Substituting this in our previous equation we then have:
Which means:
We know that , and , so substituting our values we have: