Fuse and melting point

1. A high rating fuse only indicates that the fuse will be burnt at a larger current. The resistance of which is thus much lower than that of a low rating fuse. The melting point of the fuse material is not an influential factor.

2. They could be both. Two different rated fuses could be made of the same material but with different resistances, or they could be made of different alloys.

2012-04-06 00:29:43 補充：
A high rating fuse could be made from the same material (hence same melting point) as a low rating fuse, but with a thicker dimension. Thus its resistance is lower and could carry a larger current than a low rating fuse does.

2012-04-06 00:33:49 補充：
Matematically, rate of heat dissipated at the fuse H = I^2.R (I is the current and R is the resistance of fuse).
Suppose the fuse melts if the heat produced is H, then H = (I1)^2.(R1) = (I2)^2.R2
where I1 and I2 are the max current the fuse carries for the low and high rating fuses respectively

2012-04-06 00:36:54 補充：
(cont'd)...R1 and R2 are the corresponding resistances of the fuses.
Since R2 < R1, then I2 > I1
That is, both fuses metls at the same temperature, but the high rate fuse carries a larger current than the low rate fuse.
Hence, the answer to Q1 should be NO.

1.Yes
2.Yes