The current in an inductor when energy is stored. Please help

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SUMMARY

The current in a 15mH inductor when the stored energy is 42μJ is calculated using the formula E = 1/2 L i^2. Substituting the values, the equation becomes 0.000042J = (0.5)(0.015H)(i^2), leading to i = 0.0748 A. The correct answer, rounded to two significant figures, is 0.075 A, not 0.07, as the latter only represents one significant figure.

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  • Understanding of inductance and energy storage in inductors
  • Familiarity with the formula E = 1/2 L i^2
  • Basic knowledge of significant figures in scientific notation
  • Ability to perform square root calculations
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BryceHarper
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The current in an inductor when energy is stored. Please help!

Homework Statement



What's the current in a 15mH inductor when the stored energy is 42μJ

Homework Equations



E = 1/2 L i^2

The Attempt at a Solution



.000042J = (.5)(.015H)(i^2)
.000042J = (.0075)(i^2)
.0056 = i^2
√ (.0056) = i
.0748331 = i

I need to put the answer in with only two sig figs so i put in .07 but it was wrong
What am I doing wrong?
 
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Hi BryceHarper! :smile:
BryceHarper said:
I need to put the answer in with only two sig figs so i put in .07 but it was wrong

.07 is two decimal places but only one significant figure :wink:
 


I'm dumb haha. Thanks!
 

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