Two bulbs, power, voltage, seres connection

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SUMMARY

When two bulbs, a 25 W - 110 V and a 100 W - 110 V, are connected in series to a 230 V supply, the current through each bulb must be equal due to the nature of series circuits. The resistance of each bulb can be calculated using the formula R = V^2/P. For the 25 W bulb, the resistance is 484 ohms, and for the 100 W bulb, it is 121 ohms. This significant difference in resistance will lead to unequal voltage drops across the bulbs, potentially causing the 25 W bulb to fail due to excessive voltage.

PREREQUISITES
  • Understanding of Ohm's Law
  • Knowledge of electrical power calculations
  • Familiarity with series circuit behavior
  • Ability to calculate resistance using the formula R = V^2/P
NEXT STEPS
  • Study series and parallel circuit configurations
  • Learn about power ratings and their implications in electrical circuits
  • Explore the concept of voltage division in series circuits
  • Investigate the effects of connecting devices with different power ratings
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Electrical engineering students, hobbyists working with circuits, and anyone interested in understanding the implications of connecting electrical devices in series.

math_maj0r
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Homework Statement



Two bulbs rated 25 W - 110 V and 100 W - 110 V are connected in series to a 230 V supply. What will happen?
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Homework Equations



p = vi. p = v2/r


The Attempt at a Solution



I am not sure I know how to interpret it correctly. To find the current through bulb 1, I did P1/V1 = 25/110 = .227, and for bulb 2 I did P2/V2 = 100/110 = .909. This can't be right because I1 must equal I2 since they are in series.

If I use the other formula p = v2/r and solve for resistance, i get a really big answer. i think i may be doing something wrong by plugging in 110 for v.

?
 
Physics news on Phys.org
You get a big answer ?
How much ?
 
First, consider each bulb separately.

If you connect the 25W bulb across a 110V source (as it was designed for), what is the resistance?
 

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