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

we know that,


So, by putting the values in the formula, we get

I= 180/240= 0.75A.

Fuse wire should must with stand only little more amount of current then 0.75A. so the required fuse is of 1A.