How Do Voltage and Current Behave in Series and Parallel Light Bulb Circuits?

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SUMMARY

The discussion focuses on the behavior of voltage and current in light bulb circuits, specifically a 30W and a 40W bulb connected in both parallel and series configurations to a 120V source. In parallel, each bulb experiences the same voltage of 120V, while the current through each bulb can be calculated using the formula P=IV. In series, the total voltage is divided between the bulbs, leading to different current values based on their resistances. The resistance for each bulb can be determined using the formula R=V/I derived from the power equation.

PREREQUISITES
  • Understanding of electrical power calculations (P=IV)
  • Knowledge of Ohm's Law (V=IR)
  • Familiarity with series and parallel circuit configurations
  • Ability to calculate resistance from power ratings
NEXT STEPS
  • Calculate the resistance of the 30W and 40W bulbs using their power ratings.
  • Explore the implications of connecting multiple bulbs in series versus parallel.
  • Learn about Kirchhoff's Voltage Law in relation to series circuits.
  • Investigate how total current and voltage behave in mixed circuit configurations.
USEFUL FOR

Students studying electrical engineering, educators teaching circuit theory, and hobbyists experimenting with basic electrical circuits.

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Homework Statement


Two Light bulbs, one rated 30W at 120V and another rated 40W at 120V are arranged in two different circuits.
a) they bulbs are connected in parallel to a 120V source

determine the resistance and current in both bulbs.

b) determine the resistance and current if they are connected in series


Homework Equations


P=IV

V=IR


The Attempt at a Solution



I took the power over the voltage to find the current and then plugged that into V=IR, but how does the voltage and current differ when it splits, or when it is in series?
 
Physics news on Phys.org
The load voltages for a parallel configuration is the same across each load. Each light in the parallel configuration has the same voltage.

For a series configuration the load voltages add to equal the source voltage.
 

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