Answer: An electrical fuse is composed of a thin wire of short length that is composed of tin and lead in the proportion of 75:25 percent. When the current exceeds the specified limit, the fuse melts and the circuits are broken, thereby protecting home appliances from damage. If a fuse with a higher rating is replaced with a smaller rating, the appliances may be damaged while the protective fuse remains in the circuit. This practice of using a fuse with an incorrect rating should be avoided at all costs.