Question

If fuse of 250 mA, 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?  

Answer 1

We will first calculate the current.
Here,
P = 180 W
V = 240 V
Now, power, P = `VxxI`
or, I = P/V = 180/240 = 0.75 A
So, a fuse of 1 A will be most suitable.