Why relating number on the fuse with the width of the metal strip in the fuse?

The number on a fuse indicates its current rating, which corresponds to the maximum amount of electrical current the fuse can safely handle before it blows. This rating is directly related to the width and thickness of the metal strip inside the fuse; a wider and thicker strip can carry more current without overheating. If the current exceeds this limit, the metal strip heats up and melts, breaking the circuit to protect the electrical system from damage. Thus, the dimensions of the metal strip are crucial for ensuring the fuse operates as intended.