Answer / sudarsun

Fuses work based on the principle where the fuse wire melts
when power dissipated is beyond a threshold. The power
dissipated as heat at the fuse wire is given by P=I*I*R.
Since the resistance of the fuse wire is constant (based on
the materials and diameter) for a given fuse wire, it would
be easier to rate it in terms of Ampere.

The greater the thickness, lesser the resistance, so more is
the current required to heat the wire to melting. So higher
ampere rated fuse wires are thicker and low ampere rated
wires are thinner.

Also, the power dissipated as heat on the fuses is very low,
so measuring based on power dissipated is not intuitive.

Answer / doss

fuse is one of the protection for load .also we called fuse is low melting point.current only can make heat and melt the fuse. when the load side get any problem ,load going to take over current .so the over current flow through the fuse and melt the fuse and break the circuit.fuse selection is depends upon the load.its a simple protection.

Answer / anand

power is depend on the Amps amphire only varried in circuits.
P=V *I* Cos@
Power and voltage constant only variable parts is I and Cos @.
tahts wy we are taken the amps is the reference.

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