Power Dissipation in 70W/240V Globe

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SUMMARY

The actual power dissipated by a 70W, 240V globe connected to a cord with a resistance of 0.6 ohms per wire can be calculated by first determining the total resistance in the circuit. The resistance of the bulb can be derived from its rated values, and the total current can be calculated using Ohm's Law. This approach confirms that the bulb's rated wattage is not a fixed constant but rather a function of the circuit's total resistance and voltage.

PREREQUISITES
  • Understanding of Ohm's Law
  • Knowledge of electrical resistance and power calculations
  • Familiarity with series and parallel circuits
  • Basic concepts of voltage and current
NEXT STEPS
  • Calculate the total resistance in a circuit with multiple components
  • Learn about power dissipation in resistive loads
  • Explore the relationship between voltage, current, and resistance in electrical circuits
  • Study the effects of temperature on electrical resistance
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Electrical engineers, physics students, and anyone interested in understanding power dissipation in electrical circuits.

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If you have a globe marked 70W and 240V and you connect it to one end of cord( which has two wires, each of 0.6 ohms), and the other end of the cord is connected to a 240V outlet, what is actual power dissipated by the globe?
 
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Here are a few pushes in the right direction.

The rating on the bulb (70W at 240 V) does not mean that either wattage or voltage is a "set" constant for the bulb. But from these two values, you can find a property that is constant for the bulb, specifically its resistance (assuming there is not significant difference in temperature between the rated and actual power output).

So, assume a voltge of 240V across the circuit, find the total current through the circuit (using total resistance), then find power output of the bulb.
 
Thanx for that advice, it was very helpful
 

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