An inductor of 390 turns has a radius of (8 , textcm) and a length of (27 , textcm). The permeability of free space is (1.25664 times 10-6 textN/textA²). Find the energy stored in it when the current is (0.5 , textA).
a) 0.021 J
b) 0.035 J
c) 0.042 J
d) 0.051 J