1.      What is the role of fuse, used in series with any electrical appliance? Why should a fuse with defined rating not be replaced by one with a larger rating?

Fuse has have thin wire of short length made of tin and lead in the ratio of 75: 25%. When current exceeds specified limit fuse melts and breaks the circuits thereby protecting home appliances. If a fuse is replaced by one with larger ratings, the appliances may get damaged while the protecting fuse does not burn off. This practice of using fuse of improper rating should always be avoided.