0
$\begingroup$

I read that if I simply connect two ends of a battery it would discharge really quick and it would last longer if the circuit contained e.g. a light bulb.

I wondered why is this happening and my reasoning is as follows: A battery has fixed voltage e.g. 1.5V. Therefore, no matter what components the circuit consists of, the voltage between the terminals is always 1.5V. The resistance of a mere wire is relatively low (that's what I think). Connecting a lightbulb increases the resistance. If voltage is to stay the same, then an increase in resistance must be due to decrease in current. This translates to the battery lasting longer (I don't know exactly why but it seems intuitive to me that chemical reactions that take place in the battery can "produce" only a fixed number of free electrons so lower current would mean that they're not used up as quickly).

Is my reasoning correct? If no, where did I make a mistake?

$\endgroup$
  • $\begingroup$ Questions whose answer is potentially a mere "Yes" are not good questions. $\endgroup$ – ACuriousMind Sep 2 '15 at 15:02
  • $\begingroup$ How else would I confirm validity of my reasoning? Of course, if it's wrong I expect the answer to be more than just "No" - it should point out the mistake and correct it. $\endgroup$ – Richard Smith Sep 2 '15 at 15:17
  • 1
    $\begingroup$ Instead of "the increase in resistance is due to the decrease in current", I'd say "the decrease in current is due to the increase in resistance". Otherwise, you're basically correct. Increasing the resistance reduces the current flowing from the battery. Which means it discharges more slowly. $\endgroup$ – The Photon Sep 2 '15 at 16:45
  • $\begingroup$ You're absolutely right, it was a mistake. Thanks. $\endgroup$ – Richard Smith Sep 2 '15 at 16:53

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.