Sufficient lighting for fuge?

I'm looking for a submersible light for my small fuge in the back of my nano cube 24. The light is obviously for the chaeto. In any case, on a certain auction site if you search for "submersible aquarium light" they have a 5W 12V AC light bulb. Will this be sufficient lighting for the chaeto I have growing in the back area? Keep in mind its not a big area so I wont need a lot of lighting. It is essentially a tiny little light hanging by the wire that I will put into the back of the tank.
 
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