Maximize Battery Lifetime: Drawing a Circuit

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Homework Help Overview

The discussion revolves around drawing a circuit that includes a battery and two identical bulbs, with the goal of maximizing the battery's lifetime. The subject area is primarily focused on electrical circuits, particularly the differences between series and parallel configurations.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • Participants explore the relationship between circuit configuration (series vs. parallel) and battery life, questioning how resistance affects current and power consumption. Some express uncertainty about whether a parallel or series arrangement would maximize battery life, while others seek clarification on the implications of current draw in each configuration.

Discussion Status

The discussion is active, with participants sharing their reasoning and questioning each other's assumptions. Some guidance has been offered regarding the relationship between resistance, current, and power consumption, but no consensus has been reached on the optimal circuit configuration.

Contextual Notes

Participants are working under the constraints of a homework assignment that requires them to consider the effects of circuit design on battery life without providing complete solutions. There is an emphasis on understanding the underlying principles rather than arriving at a definitive answer.

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Homework Statement



Draw a circuit the involves a battery and two identical bulbs that will maximize the lifetime of the battery. More specifically, draw a circuit that allows you to run the lights longest


Homework Equations


P = IV
V = IR
Series: R = R1 + R2
Parallel: R = 1/(1/R1 + 1/R2)


The Attempt at a Solution



I know that the equivalent resistance of the light bulbs in series is greater than the equivalent resistance in parallel. I also know that the battery provides a fixed emf. In series, there is a smaller current and a larger resistance than in parallel. I think that because parallel circuits have less resistance, if I put the light bulbs in parallel, then the battery life will be maximized. Does this make sense, or am I woefully lost in circuits? Thank you so much.
 
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physicsstudent14 said:

Homework Statement



Draw a circuit the involves a battery and two identical bulbs that will maximize the lifetime of the battery. More specifically, draw a circuit that allows you to run the lights longest


Homework Equations


P = IV
V = IR
Series: R = R1 + R2
Parallel: R = 1/(1/R1 + 1/R2)


The Attempt at a Solution



I know that the equivalent resistance of the light bulbs in series is greater than the equivalent resistance in parallel. I also know that the battery provides a fixed emf. In series, there is a smaller current and a larger resistance than in parallel. I think that because parallel circuits have less resistance, if I put the light bulbs in parallel, then the battery life will be maximized. Does this make sense, or am I woefully lost in circuits? Thank you so much.

The voltage is a constant determined by the battery. The battery lasts the longest when there is the least amount of power getting used. Since P=IV and the voltage drop across the entire circuit is a constant determined by the battery, then the current is the only factor left. Is the current high when there is a large or small resistance?
 
If you put the bulbs in parallel, will they draw more current or less current?

If the bulbs draw more current, will the battery be able to supply energy for a greater or lesser period of time?

(Hint: You want to minimize the rate of energy dissipation from the battery.)

EDIT: NotMrX has said basically the same things, a few minutes before me.
 
Because V = IR, and I = V/R, then the larger current will coincide with the smaller resistance (parallel circuit). If the parallel circuit has a small resistance and larger current, then it will use up more power, so the series circuit maximizes battery life, right? Thanks.
 

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