Question

Two fuse wires of same length are rated 5A and 20 A. Which of the fuse wire is thicker and why?

Answer 1

1. Resistance of a wire depends upon the length and the cross-sectional area of the wire.
2. The longer a wire is, the greater resistance it has because electrons must travel a longer distance to get from one end to the other.
3. The larger the cross-sectional area, the lower the resistance because the electrons have more space to move through.
4. Larger cross-sectional area means a larger thickness.
5. A thicker wire has more space for the electrons to flow, so it can pass more current through it.
6. So, a wire having a current rating high $(i.e.20A)$as compared to a low current rating $(i.e.5A)$, the high rated wire will be thicker. It also has less resistance.
7. Thus,$20A$ wire will be having more thickness.