Constructing experiment to prove P=IV

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SUMMARY

The discussion focuses on constructing an experiment to demonstrate the relationship P=IV, specifically proving that power (P) is maximized when internal resistance (r) approaches zero and total resistance equals normal resistance (R). A practical approach involves using a 12-volt car battery with an internal resistance of approximately 0.01 ohms and a 1-ohm resistor submerged in 225 cc of water. By measuring the temperature increase of the water, participants can calculate power output, confirming that P=IV holds true with minimal energy loss due to internal resistance.

PREREQUISITES
  • Understanding of electrical power calculations (P=IV)
  • Knowledge of internal resistance in circuits
  • Familiarity with calorimetry and temperature measurement
  • Basic circuit assembly skills
NEXT STEPS
  • Research methods for measuring internal resistance in batteries
  • Explore calorimetry techniques for energy transfer measurements
  • Study the effects of resistance on power output in electrical circuits
  • Learn about practical applications of Ohm's Law in experiments
USEFUL FOR

This discussion is beneficial for physics students, educators conducting practical experiments, and anyone interested in electrical engineering principles related to power and resistance.

PhysicsLearne
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Not sure if the title is clear enough, but basically I've got a practical in a couple of days time and I have to construct an experiment to prove that P=IV by proving that P is greatest when the value of r (internal resistance) is zero and total resistance is equal to R (normal resistance).

I'm quite confused at what this is actually asking me to to do. Any ideas.

thanks
 
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Is this a real project or a virtual project? One accurate way to measure power is to heat a resistor in a calorimeter, and measure the energy transferred to a cup of water. Suppose you had a 12-volt car battery with an internal resistance with about r = 1/100 ohm. Get a R=1 ohm resistor and put it in about a cup (about 225 cc) of water, and connect it to the battery. Get a thermometer and measure the rate at which the water heats up. P = I*V = V^2/R = 144 watts. Only about 1% of the battery power is lost in the internal resistance r.
 
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