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A solenoid having area A and length 'l' is filled with a material having relative permeability 2. The magnetic energy stored in the solenoid is :
(1) B2Al4 0
Let B be the magnetic field inside the solenoid.
Permeability of the core = r 0 = 2 0
Magnetic energy density u = B22 = B24 0
Volume of the solenoid = Al
Energy U = u Al = B2Al4 0
Answer: (1)
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