Skip to main content

Learning Introductory Physics with Activities

Paul J. Emigh, Rebecka Tumblin, Kathryn Hadley, Danielle Skinner

Section 25.13 Challenge - Circuits: Intro

Explanation 25.13.1. Circuit I.

Figure 25.13.1. Circuit diagram.
The circuit above shows four identical bulbs connected to an ideal battery. The switch is initially closed.
  1. Rank the bulbs according to brightness, in order from brightest to dimmest. If two bulbs have the same brightness, indicate that explicitly.
  2. When the switch is opened, will bulb A get brighter, get dimmer, or remain the same brightness?
  3. When the switch is opened, will bulb B get brighter, get dimmer, or remain the same brightness?

Explanation 25.13.2. Circuit II.

Figure 25.13.2. Circuit diagram.
Rank the light bulbs shown above according to brightness. If any bulb does not light, or if you do not have enough information, state so explicitly.
In particular, explain your reasoning for how you ranked each of the following pairs of bulbs:
  1. A & B
  2. A & C
  3. A & D
Tip.
Use voltage diagrams to help your reasoning.

Subsection Metacognitive Reflection

We came up with a model for circuits this week, based on the brightness of a lightbulb. Restate the model here in your own words, and explain why you cannot use Ohm’s law for real lightbulbs.
PrevTopNext