Answer to Question 10



A solenoid has a diameter of 1.5 cm and a length of 5.0 cm.  It has 200 turns and core of magnetic material that has a relative permeability of 130.  It has a current of 4.5 A flowing in it.  Calculate the energy density.  State the correct unit.

The diameter is irrelevant, as area does not come into the equation.




U = [4p 10-7 H m-1 130 (200 turns)2 (4.5 A)2] [2 (5.0 10-2 m)2] = 2.6 104 J m-3