Question

wire A has a lower melting point than wire B.which wire would you choose to make a fuse to (a) allow more current to pass through and (b) allow less current to pass through ? give reasons for your answer

Answer 1

A fuse is made up of metals that have high resistance and low melting point so that the fuse can break easily when excess current is passed through it.

So (a) is the best metal to make a fuse.

Answer 2

(a) allow more current to pass through: For this purpose we would have to choose wire B because current generates a lot of heat and as such wire B with higher melting point will not melt from the heat.  

(b) allow less current to pass through: For this purpose we can choose wire A as due to low current flow the wire will net get heated enough to melt the wire.