If fuses of 250mA, 500mA, 1A, 5A, and 10A were available, which one would be the most suitable for protecting an amplifier rated at 240V, 180W?

Given,

P = 180W V = 240V

We know that, P = VI

I = P/V = 180/240 = 0.75A

Therefore, the fuse wire should have the capacity to withstand a current of 0.75A. Therefore, 1A fuse is more suitable.