Inductance 03 - Energy Stored in the B Field of an Inductor

SAFARI DIRECTOR: Ian

 

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OPENING QUESTIONS: There is a recurring *style* of equation for various types of energy. Comb your thoughts and see if you can suggest what that might be.

 

 

Hint:

1/2kx2, 1/2mv2

 

With that in mind, please suggest an equation for calculating the energy stored in the magnetic field of an inductor.

OBJECTIVE:  I will be able to calculate energy stored in the magnetic field of an inductor during today's class.

WORDS/FORMULAE FOR TODAY

TERMS

  • self induction/back emf
  • Inductance
  • solenoid ("A coiled wire with n loops per unit length")

CONSTANTS:

 

UNITS:

      • henry = (volt)(sec)/amps

FORMULAE:

      • UB = 1/2Li2
      • εL = L(di/dt)
      • Kirchoff Amended: ε - iR - L(di/dt) = 0
      • B = μonI
        • n = number of loops per unit length
        • I = current
      • εL = -L(di/dt) AP = -L(dI/dt)
        • dI/dt = change in current
        • L = propotionality constant depending on the "geometry of the loop and other physical characteristics"
      • L = NφB/i
        • N = number of loops (or coils if you prefer)
        • i = current that may vary with time (hence the lower case)

WORK O' THE DAY

Please write the full form of Kirchoff's Law (include inductance)

How many OTHER equations do we have for EMF?

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Coursework: Problem 15 and 19 on page 990

STUDY GUIDE: