Multiple choice Current through Bulb A

Mdhiggenz
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Homework Statement



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Homework Equations





The Attempt at a Solution



First I originally tried using kichhoff's rules, but didn't get far.

What is throwing me off is they are giving me the current of the battery instead of the voltage. Since I know circuits in parallels all have the same voltage, I don't really know what to do.
 
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Are you familiar with a current divider? Which path do you think allows more current--through A or through B-C?
 
the path through A allows for current, since the path through B-C gets split up into two small currents.
 
Both paths allow for current. Path A allows for more current because it has less resistance. Knowing this you can solve the multiple choice question by process of elimination.

Knowing what a current divider is and how to use is helpful: http://physics.eou.edu/courses/phys_223/sg2/node6.html

If you want to solve another way, find the equivalent resistance [edit-- oops no resistance specified. So assume 1Ω per bulb. You will get a resulting voltage], then find the voltage, then find the individual currents. All three of these paths lead to the same answer.
 
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The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

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