Thor and hulk stand there as Beta Ray Bill fires one lightning bolt at a time at them. Thor is not allowed to use shields or absorb the attacks with his hammer. How many full powered lightning bolts can each character take before being KO'ed? Hulk is current Hulk, he is allowed to get madder.
Is it even possible for Bill to KO current Hulk in this way?
Anyone remember way back when lightning REFRESHED Thor? Now his own lightning hurts him more than it hurts anyone else. And to the OP, yes, lightning can and has KO'ed the Hulk, though I'm sure that based on the stips, the Hulk would last a LOT longer than Thor here. There's no question about it in my mind.