Current through a coil in a magnetic field

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SUMMARY

The discussion centers on calculating the average current flowing through a coil with 90 turns, a resistance of 6 ohms, and an area of 28 cm² moving through magnetic fields of 0.02 Tesla and 0.42 Tesla over 3 seconds. The correct formula for EMF is applied, but the area must be converted from cm² to m², resulting in an area of 0.0028 m². The recalculated EMF yields 0.336 volts, leading to an average current of 0.056 amps, not 0.56 amps as initially calculated. The discrepancy arises from the incorrect unit conversion of area.

PREREQUISITES
  • Understanding of electromagnetic induction principles
  • Familiarity with Ohm's Law
  • Knowledge of unit conversions, particularly area from cm² to m²
  • Basic proficiency in using formulas for calculating EMF
NEXT STEPS
  • Study the principles of Faraday's Law of Electromagnetic Induction
  • Learn about unit conversions in physics, focusing on area and volume
  • Practice problems involving EMF calculations with varying magnetic fields
  • Explore applications of electromagnetic induction in real-world scenarios
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Students in physics, electrical engineers, and anyone interested in understanding electromagnetic induction and current calculations in coils.

cheeseboy
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Question:

A coil of 90 turns, of resistance 6 ohm and area 28 cm² moves from a
uniform magnetic field of 0.02 Tesla to one of 0.42 Tesla in 3.0 second.
What average current flows in the wire (in amp) ?

Relevant equations:

EMF= (Area * Rate of change of magnetic flux) * Number of turns

I = EMF/Resistance

Attempted Solution:

EMF= ((0.28^2) * ((0.42-0.02)/3)) * 90 turns = 3.36

I = EMF/Resistance = 3.36/6 = 0.56 amps (i believe this is correct)

however answer given is 0.0056 amps where am I missing this factor of 100?
 
Last edited:
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cheeseboy said:
Question:

A coil of 90 turns, of resistance 6 ohm and area 28 cm² moves from a
uniform magnetic field of 0.02 Tesla to one of 0.42 Tesla in 3.0 second.
What average current flows in the wire (in amp) ?

Relevant equations:

EMF= (Area * Rate of change of magnetic flux) * Number of turns

I = EMF/Resistance

Attempted Solution:

EMF= ((0.28^2) * ((0.42-0.02)/3)) * 90 turns = 3.36

I = EMF/Resistance = 3.36/6 = 0.56 amps (i believe this is correct)

however answer given is 0.0056 amps where am I missing this factor of 100?
28\;cm^2 \neq 0.28\;m^2
 

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