Find the inductance of the coil if, at a current of 2A, the energy of the magnetic field in it is 4J.

These tasks: I (current in the considered coil) = 2 A; W (value of the magnetic field energy) = 4 J.
To determine the inductance of the coil in question, we use the formula: W = L * I ^ 2/2, whence L = 2 * W / I ^ 2.
Let’s calculate: L = 2 * 4/2 ^ 2 = 2 G.
Answer: The coil in question must have an inductance of 2 H.

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