Question

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

• A. both wire will be same thickness.
• B. 20 A wire is more thicker
• C. 5 A wire more thicker
• D. none of these.

Answer 1

Answer: (B)

20 A wire is more thicker

The fuse must always be connected to the mains and it must be of correct value. For example, a 15-ampere fuse should trip when the current through it exceeds 15 amperes. A 20-ampere fuse should blow when the current through it exceeds 20 amps.
As we know, the cross-sectional area of the wires will affect the amount of resistance. Wider wires have a greater cross-sectional area. Water will flow through a wider pipe at a higher rate than it will flow through a narrow pipe. This can be attributed to the lower amount of resistance that is present in the wider pipe. In the same manner, the wider the wire, the less resistance that there will be to the flow of electric charge. When all other variables are the same, charge will flow at higher rates that is, more current through wider wires with greater cross-sectional areas than through thinner wires.
Hence, the 20 A wire is the thicker wire as more amount of current flow through it than the 5 A wire.