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What is the proper way to connect two light bulbs in a circuit? in series or in parallel and why?

My thought is that it's better to hook them in parallel, since if we take into account Ohm's Law, the sum of their resistance will be less than when connected in series therefore the battery will last longer.

What do you think?

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What is your criterion for "better"? Power usage or brightness, or something else? Also, since I imagine you're studying this kind of thing, have you tried figuring it out yourself? Is there some particular aspect of solving the problem that gives you trouble? – David Z Mar 5 '12 at 20:08
By the way, "What do you think?" is not really a good way to end a question around here. We strive to collect answers, not opinions. – David Z Mar 5 '12 at 20:09
I messed this up too didn't I :) – dom Mar 5 '12 at 20:12
Well it could be asked better, but it's a better question for this site than your other one... and in any case, don't worry about it, you're not offending anyone or anything like that! As long as you're willing to take some constructive advice on how best to participate in the site, we're happy to have you and your questions here. We understand that people don't come in automatically knowing how we do things around here. – David Z Mar 5 '12 at 20:16
Thank you so much David! I'll try to update my question so it makes more sense. – dom Mar 5 '12 at 20:18
up vote 2 down vote accepted

If you want the battery to last longer, you want the resistance to be HIGHER. $P = V^2/R$. Connect in parallel for bright bulbs, connect in series for dim bulbs over longer time.

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The only real answer is: in parallel, because if one bulb burns, the other one still burns. That's the answer chosen for a lot of daily-life items (your home, car etc) where, if one item fails (like the hairdryer), the others (like the light bulbs) should still burn.

This is not really the answer yet to what you have asked for, because your question is like: should I buy a brighter handheld light which shines for a shorter time or a not so bright one, which lasts longer?

So here is your real answer: Whatever your needs are...

(do you understand? it is not about voltage (btw this should just be right for your bulbs) but about energy)

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