I should have said... "can be any value above!" (sorry, I assumed when you said you knew a little that you would know not to go that low! Pots are obviously available in lots of resistance values, but 1k, 5k, 10k, 22k, 47k+ etc are the more common ones)
Yep, a 20 ohm trim pot would generate a bit of current with 12V across it!
Irving is right, a positive gate relative to source voltage turns the thing on (n-channel, p-channel moshfestch. schmoshfesh) But the test I poropsed is still valid, as you turn the wiper in the direction towards 0V with the pot wiper, eventually the FET should turn off (got to establish if it's possible to turn your particular fet off & at what voltage)
Cheers Irving ...I'll get me coat!