An LR circuit having a time constant of 50 ms is connected with an ideal battery of emf `epsilon` . Find the time taken for the magnetic energy stored in the circuti to change from one fourth of the steady state value to half of the steady stae value.

Explanation

To solve the problem of finding the time taken for the magnetic energy stored in an LR circuit to change from one-fourth of the steady-state value to half of the steady-state value, we can follow these steps:

### Step 1: Understand the steady-state magnetic energy
The magnetic energy \( U \) stored in an inductor at steady state is given by the formula:
\[ U = \frac{1}{2} L I^2 \]
where \( I \) is the steady-state current. The steady-state current \( I_0 \) can be expressed as:
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