Rita use the fuse wire with 100 ampere specification in a circuit at home which draws a maximum current of 20 ampere when all devices in the circuit are switched on do you think she used the correct fuse wire what will you advise her to do
Answers
What is a Fuse Wire ?
A fuse wire is made of an alloy with a low melting point so that whenever excessive current flows through the circuit, the wire melts due to Joule's Law of Heating and the appliances are not harmed due to excessive current.
Did Rita use the correct fuse wire ?
No. She didn't use the correct fuse wire because, the maximum allowable current in the circuit is 20 Amp but she used a fuse wire that will melt only if the current in the circuit exceeds the magnitude of 100 Amp.
So, a current of magnitude > 20 Amp and < 100 Amp can also flow into the circuit (eg, 40 Amp, 50 Amp, 80 Amp), therefore, harming the appliances in the circuit.
An advise for Rita
Rita should replace the 100 Amp rating fuse by a 20 Amp rating fuse so that the fuse wire melts only if the current in the circuit exceeds 20 Amp.
It means, now, if any current of magnitude of more than 20 Amp (eg, 40 Amp, 50 Amp, 80 Amp), flows into the circuit, the fuse wire will melt and the appliances will be saved.
Answer:
No, Rita did not use the correct fuse wire. The ampere rating of a fuse should not exceed the current carrying
capacity of the circuit except in some cases.
In the given circuit, she should use a fuse wire with 20 amperes specification.