Question:
An inductor of inductance
\[
5\,\text{H}
\]
is carrying an electric current of
\[
4\,\text{mA}.
\]
Then the energy stored in the inductor is
An inductor of inductance
\[
5\,\text{H}
\]
is carrying an electric current of
\[
4\,\text{mA}.
\]
Then the energy stored in the inductor is
Show Hint
For an inductor,
\[
\boxed{U=\frac12 LI^2}
\]
Always convert current from mA to A before substitution.
\[
1\,\text{mA}=10^{-3}\,\text{A}.
\]
Updated On: Jul 29, 2026
- \[ 50\,\mu\text{J} \]
- \[ 1000\,\mu\text{J} \]
- \[ 40\,\mu\text{J} \]
- \[ 20\,\mu\text{J} \]
Show Solution
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The Correct Option is C
Solution and Explanation
Concept:
The energy stored in an inductor is
\[
U=\frac{1}{2}LI^2,
\]
where
\[
L=\text{inductance},
\qquad
I=\text{current}.
\]
Step 1: Write the given data. \[ L=5\,\text{H}, \] \[ I=4\,\text{mA} =4\times10^{-3}\,\text{A}. \]
Step 2: Substitute into the energy formula. \[ U = \frac12(5)(4\times10^{-3})^2. \] \[ = \frac52(16\times10^{-6}). \] \[ = 40\times10^{-6}\,\text{J}. \] \[ = 40\,\mu\text{J}. \]
Step 3: Identify the correct option. \[ \boxed{U=40\,\mu\text{J}} \] Therefore, \[ \boxed{\text{Answer = (C)}} \]
Step 1: Write the given data. \[ L=5\,\text{H}, \] \[ I=4\,\text{mA} =4\times10^{-3}\,\text{A}. \]
Step 2: Substitute into the energy formula. \[ U = \frac12(5)(4\times10^{-3})^2. \] \[ = \frac52(16\times10^{-6}). \] \[ = 40\times10^{-6}\,\text{J}. \] \[ = 40\,\mu\text{J}. \]
Step 3: Identify the correct option. \[ \boxed{U=40\,\mu\text{J}} \] Therefore, \[ \boxed{\text{Answer = (C)}} \]
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