A long circular tube of length 10 m and radius 0.3 m carries a current I along its curved surface as shown . A wire – loop of resistance 0.005 ohm and of radius 0.1 m is placed inside the tube its axis coinciding with the axis of the tube . The current varies as I = I0 cos ( 300 t ) where I0 is constant. If the magnetic moment of the loop is Nμ 0I0 sin( 300 t ), then ‘N’ is