You are making a snack for you some friends to help0 you get ready for a full night of studing. You decide that coffee, toast and popcorn would be a good start. You turn on the toaster (900 W), place some popcorn in the microwave (1200 W), and turn it on. Because your apartment is an older building, the fuse (10 A rating) may blow when you turn on too many appliances at `220 V`.
(i) Should you suggest the coffeemaker (600 W) ?
(ii) Check the answer to part (i).
(iii) If not, suggest an alternative to start the coffeemaker.
(iv) Which human quality corresponds to blowing of the fuse ?

Explanation

(i) `I_("toaster") = (P_("toaster"))/(V) = (900 W)/(220 V) = 4.1 A`
`I_("m-wave") = (P_("m - wave"))/(V) = (1200 W)/(220 V) = 5.5 A`
`I_("c-maker") = (P_("c-maker"))/(V) = (600 W)/(220 V) = 2.8 A`
The current through the fuse is the sum of these currents, i.e., `I_("fuse") = 4.1 A + 5.5 A + 2.8 A = 12.4 A`,
which is more than the fuse rating `10 (A)`
(ii) Maximum power that can be delivered by a `220 V` circuit that has a `10 A` fuse
=`I_(max) (V) = (100 A)(220 V) = 2200 W`
Total power needed to run the three appliances simultaneously `= 900 W + 1200 W + 600 W = 2700 W`
Which is `480 W` more than the circuit deliver.
(iii) The coffeemaker can be plugged into an outlet of a different circuit than the outlet for the toaster and the microwave without blowing the fuse.
(iv) Sacrifice. To save the rest of the appliancies in the circuit, the fuse itself melts.