Tuesday, October 7, 2008

Will electricity bypass a resistance?



Hi all, I got an interesting question again from my tuition gal. She ask me about circuit as shown above. Her question is will electricity bypass a resistance like a bulb end up the bulb will not light up (like the pic on the right). I ever learn that before and think it should bypass. So to double confirm I carried out the experiment. True enough it really bypass and the bulb which is after the bypass connection did not like up.

So what if we change the direction of bypass (see pic on the left). Now we put the bulb nearer to the battery followed the bypass. Some electricity did pass through the bulb as the bulb is lighted dimly (maybe it located nearer the battery) but most of them still go through the bypass.

So you doubt maybe is my battery is weak and is not lesser electricity going through my bulb. So this picture below shows that without the bypass and using the SAME battery and SAME bulb, it actually can be lighted brightly. This can prove that most of the electricity go through the bypass.

Then I tried using a bulb with greater resistance (A). Hoping that only the bulb with lower resistance (B) will light up as I assume the electricity will bypass the bulb with lower resistance. But then both bulb still light up (see pic on the left above, the one nearer to the battery has a higher resistance). You can say that lesser electricity is pass through the Bulb (A) since it is dimmer, but I tired to change the orientation and put bulb (B) nearer to the battery. Bulb (A) is still dimmer (Not shown). So I can assume is due to the electricity from the bulb is not strong enough to light up Bulb (A). If not when Bulb (B) is placed nearer to the battery, the electricity may have pass through it (since lower resistance than bulb (A)) and bypass Bulb (A) but why both bulb still light up?
So what I can conclude from this is when there is a more direct connection of a closed circuit the electricity will choose the most direct one. However when both way is blocked by a resistance, it will not prefer the one with a lower resistance, but will still pass through both way.

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