A refrigerator of 450 W works on a 230 V supply. Which fuse suits it: 3 A, 13 A or 30 A? Explain.
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
A refrigerator of works on a supply. Which fuse suits it: , or ? Explain.
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. Normal current. .
Step 2. The choice. is just above this. or would let a dangerous fault current flow before melting.
Answer: the fuse.
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