Solving a problem in physics section 64 point 5 electr

Solving a problem in physics section 64 point 5 electr

5. How much time you need to increase the strength of the current in the solenoid to the magnetic field energy density in it has grown in 16 times? In how many times to increase the number of turns per unit length of the solenoid to magnetic field energy density at the same value of current quadrupled?

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Detailed solution. Decorated in Microsoft Word 2003. (Target decided to use formula editor)