HardPhysicsHigh School (9–10)Electricity & Magnetism › Current ElectricityNumericalConceptualBoard Exam
A kitchen on a 220 V supply has a kettle of 1500 W, a toaster of 800 W and a refrigerator of 200 W…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
A kitchen on a supply has a kettle of , a toaster of and a refrigerator of , all on together. Will a fuse hold? Will a fuse hold?
Need a reminder? The key ideaShow
Joule's law: . Power , in watts. A fuse, in the live wire, melts when the current is too large.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. Total power. .
Step 2. Current. .
Step 3. The fuses. The fuse melts; the fuse holds.
Answer: : no. : yes.
Check. Switching off the toaster brings it down to .
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