Question

2
A fuse of rating 3 A is fact placed in
Series before an application of 1 kw
oft operating at 220v. Will the fuse work 2
& Justify your answer.​

Answer 1

Answer:

No the fuse will melt as you connect it and switch the circuit on

Explanation:

See the power is 1000 w (1KW) so

p=v^2/r

Apply the p and v to obtain resistance which is coming to be 48.4 ohms and by this we obtain the current through the circuit to be 4.54 amp just by the ohms law

220v/48.4ohm =4.54 amp

Therefore the fuse will melt as it has a rating of 3 ampere because of overload of fuse by 1.54 ampere .

For the fuse to work it should be of either equal to 4.54 if the potential is constant . Or greater than the 4.54 ampere upto 5 amp max rating so that potential fluctuations is handled by it . If its 3 ampere it will just melt away and cannot be used for this circuit .