Tag: electromagnetic induction and alternating currents

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Questions Related to electromagnetic induction and alternating currents

Multiple choice mutual inductance electromagnetic induction electromagnetic induction and alternating currents physics

Mutual inductance of a system of two thin coaxial conducting loops of radius each, their centers separated by distance $d (d >>r)$ is 

  1. $\mu _0\pi r^4d^3$
  2. $\dfrac{\mu _0\pi r^4}{2d^3}$
  3. $\dfrac{\mu _0\pi r^4}{d^3}$
  4. $\dfrac{\mu _0\pi r^4 d^3}{4}$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The mutual inductance between two small coaxial loops separated by distance d is M = (mu_0 * pi * r1^2 * r2^2) / (2 * d^3). Given r1 = r2 = r, M = (mu_0 * pi * r^4) / (2 * d^3).

Multiple choice mutual inductance electromagnetic induction electromagnetic induction and alternating currents physics

The coefficient of mutual inductance, when magnetic flux changes by $\displaystyle 2\times { 10 }^{ -2 }Wb$ and current changes by 0.01 A is :

  1. 8 henry

  2. 4 henry

  3. 3 henry

  4. 2 henry
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

We know that

$\displaystyle \phi =Mi$
$\displaystyle d\phi =Mdi$

$\displaystyle M=\frac { d\phi  }{ di } =\frac { 2\times { 10 }^{ -2 } }{ 1\times { 10 }^{ -2 } } =2$ henry