Why doesn't a resistor burn up when its power rating is exceeded?

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SUMMARY

The discussion centers on a 10-ohm resistor rated at 1W that was subjected to a power of 10W without burning up. The key conclusion is that the resistor's power rating does not account for external cooling methods, such as water, which can absorb excess heat. This phenomenon allows the resistor to operate beyond its rated power without failure. The underlying principle is that effective heat dissipation can prevent thermal damage to components.

PREREQUISITES
  • Understanding of electrical resistance and Ohm's Law
  • Familiarity with power ratings of resistors
  • Basic knowledge of heat transfer principles
  • Experience with experimental setups involving electrical components
NEXT STEPS
  • Research the thermal management of electronic components
  • Learn about the effects of water cooling on electrical devices
  • Study the specifications and ratings of resistors in detail
  • Explore the principles of heat dissipation in electrical circuits
USEFUL FOR

Electrical engineers, physics students, and anyone involved in designing or experimenting with electronic circuits will benefit from this discussion.

sarahjt1
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Homework Statement



The heating resistor is rated at 10ohms and 1W. By how much was its power exceeded? Why didn't the resistor burn up?

This is a question taken from an Electrical Equivalent of Heat lab assignment... here is a link to the exact same lab we did...

http://www.kbcc.cuny.edu/academicDepartments/PHYSCI/physics_12_14/pdf/Experiment4_EEquivalent_Heat.pdf

Homework Equations



P=V^2/R where V=10ohms and R=10ohms

The Attempt at a Solution



P=10W but the resistors rating was 1W and I don't really know why it didn't burn up. My only guess is that some of the power was lost due to the water absorbing some of the energy given off by the resistor?

Help! :confused:
 
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sarahjt1 said:
P=10W but the resistors rating was 1W and I don't really know why it didn't burn up. My only guess is that some of the power was lost due to the water absorbing some of the energy given off by the resistor?

Your guess is correct. The ratings of power resistors do not take into account cooling them with water.
 

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